Energy storage system having common-mode arc detection function, and optical storage device

Abstract

An energy storage system having a common-mode arc detection function, and an optical storage device. The energy storage system comprises a battery cluster (112), a common-mode current detection unit (1422) and a controller (141), wherein the controller (141) is used for controlling, when a frequency domain component of a common-mode current detected by the common-mode current detection unit (1422) is greater than a first preset amplitude, the disconnection of the path between the battery cluster (112) and an output end of the energy storage system. Thus, the accuracy and effectiveness of arc phenomenon detection can be improved, detection errors are lowered, and the use safety of the energy storage system is improved.

Description

Energy storage system and optical storage device with common-mode arc detection function

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on December 6, 2023, with application number 202311666111.1 and application name “A kind of energy storage system and optical storage device with common-mode arc detection function”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of new energy technology, and in particular to an energy storage system and a photovoltaic storage device with a common-mode arc detection function. Background Art

[0004] As a product with bidirectional energy exchange, energy storage systems can serve as backup power sources, smooth power generation, and achieve peak load shifting and valley shifting on the user side. As an energy source, electrical safety is crucial. Over time, faults such as poor contact, aging components or insulation, and leakage can occur in energy storage systems, increasing the likelihood of arcing. The sparks and high temperatures caused by arcing can easily cause fires within the energy storage system, significantly reducing its safety. Therefore, effectively and accurately detecting arcing in energy storage systems has become a pressing issue.

[0005] Summary of the Invention

[0006] The present application provides an energy storage system and a photoelectric storage device with a common-mode arc detection function, which are used to effectively and accurately detect arcing phenomena in the energy storage system and improve the safety of the energy storage system.

[0007] In a first aspect, embodiments of the present application provide an energy storage system comprising: a battery cluster, a common-mode current detection unit, and a controller. The battery cluster includes at least two battery modules connected in series. One end of the common-mode current detection unit is connected to the positive output terminal of the battery cluster, and the other end of the common-mode current detection unit is connected to the negative output terminal of the battery cluster. The common-mode current detection unit is configured to detect common-mode current in the connected circuit. The controller is configured to disconnect the path between the output terminal of the battery cluster and the output terminal of the energy storage system when the frequency domain component of the common-mode current is greater than a first preset amplitude. It should be understood that the first preset amplitude can be determined based on the frequency domain component of the current corresponding to the occurrence of arcing to avoid and eliminate the arcing phenomenon, and the specific value is not limited herein.

[0008] In this way, the controller can analyze the common-mode current. Since the current has multiple frequency domain components, the various frequency domain components in the common-mode current can be determined. Since the current when arcing occurs has different components in different frequency domains, the components in each frequency domain vary greatly, and some frequency domain components may be large, while some frequency domain components may be small, while the current when no arcing occurs has the characteristics that the components in different frequency domains are all 0 and no large frequency domain components will appear, the determined frequency domain components can be analyzed. If a frequency domain component is greater than the first preset amplitude, it means that there is a large frequency domain component in the common-mode current. At this time, it can be determined that the common-mode current is the current when arcing occurs, and it can be determined that arcing has occurred, which improves the accuracy and effectiveness of arcing detection and reduces detection errors. In addition, the controller can control the path between the battery cluster and the output end of the energy storage system to disconnect, realize arc extinguishing or protection action, so that arc extinguishing measures can be taken in time when arcing occurs, thereby improving the safety of energy storage system use.

[0009] It is worth noting that the common-mode current detection unit can detect the current flowing out of the positive output terminal (denoted as current a) and the current flowing into the negative output terminal (denoted as current b). If the difference between current a and current b is 0, it means that the current flowing out of the positive output terminal is equal to the current flowing into the negative output terminal, so there is no residual current, that is, there is no leakage current. At this time, arcing will not occur, and the common-mode current is 0. If the difference between current a and current b is not 0, it means that there is residual current, that is, there is leakage current, and the common-mode current is not 0. If sparking occurs when the common-mode current is not 0, the amplitude of the common-mode current in different frequency domains will vary greatly. When the frequency domain component is greater than the first preset amplitude, it can be determined that arcing occurs. Therefore, the presence of leakage current does not mean that arcing occurs, but if sparking occurs when there is leakage current, arcing is likely to occur. Therefore, by comparing the frequency domain component of the common-mode current with the first preset amplitude, it can be determined whether arcing occurs.

[0010] Optionally, the energy storage system may further include a differential-mode current detection unit connected to the positive or negative output terminal of the battery cluster, the differential-mode current detection unit being configured to detect differential-mode current in the connected circuit. The controller is further configured to disconnect the path between the output terminal of the battery cluster and the output terminal of the energy storage system when the frequency domain component of the differential-mode current is greater than a second preset amplitude. Similar to common-mode current, when the frequency domain component of the differential-mode current is greater than the second preset amplitude, it indicates the presence of a large frequency domain component in the differential-mode current. In this case, it can be determined that the differential-mode current is the current at the time of arcing, thereby confirming the presence of an arcing phenomenon. This improves the accuracy and effectiveness of arcing phenomenon detection and reduces detection errors. It should be understood that the second preset amplitude can be determined based on the frequency domain component of the current corresponding to the occurrence of the arcing phenomenon to avoid and eliminate the arcing phenomenon. The specific value is not limited herein.

[0011] The differential mode current detection unit may include a positive differential mode current detection unit, or the differential mode current detection unit may include a negative differential mode current detection unit, or the differential mode current detection unit may include a positive differential mode current detection unit and a negative differential mode current detection unit. The specific structural arrangement of the differential mode current detection unit may be determined according to actual conditions and is not limited here. When the differential mode current detection unit includes a positive differential mode current detection unit and a negative differential mode current detection unit, the positive differential mode current, the negative differential mode current, and the common mode current may be comprehensively combined for judgment, thereby further improving the accuracy and effectiveness of arcing detection and reducing detection errors.

[0012] The positive differential mode current detection unit can detect current a, which can be considered a positive differential mode current. The negative differential mode current detection unit can detect current b, which can be considered a negative differential mode current. When sparking occurs, the amplitudes of currents a and b vary significantly in different frequency domains. When the frequency domain component of current a or current b exceeds a second preset amplitude, arcing is determined. Therefore, by detecting the positive differential mode current or the negative differential mode current, it is also possible to determine whether arcing is occurring.

[0013] In addition to the battery cluster, detection device, and controller, the energy storage system may also include a DCDC conversion circuit, with the positive input of the DCDC conversion circuit connected to the positive output of the battery cluster, and the negative input of the DCDC conversion circuit connected to the negative output of the battery cluster. In this case, the positive differential mode current detection unit, the negative differential mode current detection unit, and the common mode current detection unit may be located in the following locations:

[0014] Regarding the positive differential-mode current detection unit: the positive differential-mode current detection unit is connected to the positive input terminal of the DCDC converter circuit. In this case, the positive differential-mode current detection unit can detect the differential-mode current at the positive input terminal of the DCDC converter circuit. Since the positive input terminal of the DCDC converter circuit is connected to the positive output terminal of the battery cluster, the current at the positive input terminal of the DCDC converter circuit detected by the positive differential-mode current detection unit can be regarded as the differential-mode current at the positive output terminal of the battery cluster. Therefore, when arcing occurs at the positive output terminal of the battery cluster, it can be detected as soon as possible and protective measures can be taken in a timely manner to prevent damage to the battery cluster and the DCDC converter circuit, thereby further improving the safety of the energy storage system. Alternatively, the positive differential-mode current detection unit is connected to the positive output terminal of the DCDC converter circuit. In this case, the positive differential-mode current detection unit can detect the differential-mode current at the positive output terminal of the DCDC converter circuit. Therefore, when arcing occurs at the positive output terminal of the DCDC converter circuit, it can be detected as soon as possible and protective measures can be taken in a timely manner to prevent damage to the DCDC converter circuit and the DC-AC converter circuit, thereby further improving the safety of the energy storage system. Among them, the specific implementation structure of the positive differential mode current detection unit can be any structure that can realize the positive differential mode current detection function known to those skilled in the art, such as but not limited to any one of a shunt and a current transformer, and is not specifically limited here.

[0015] Regarding the negative differential-mode current detection unit: the negative differential-mode current detection unit is connected to the negative input terminal of the DCDC converter circuit. In this case, the negative differential-mode current detection unit can detect the differential-mode current at the negative input terminal of the DCDC converter circuit. Since the negative input terminal of the DCDC converter circuit is connected to the negative output terminal of the battery cluster, the current at the negative input terminal of the DCDC converter circuit detected by the negative differential-mode current detection unit can be regarded as the differential-mode current at the negative output terminal of the battery cluster. Therefore, when arcing occurs at the negative output terminal of the battery cluster, it can be detected as soon as possible and protective measures can be taken in a timely manner to prevent damage to the battery cluster and the DCDC converter circuit, thereby further improving the safety of the energy storage system. Alternatively, the negative differential-mode current detection unit is connected to the negative output terminal of the DCDC converter circuit. In this case, the negative differential-mode current detection unit can detect the differential-mode current at the negative output terminal of the DCDC converter circuit. Therefore, when arcing occurs at the negative output terminal of the DCDC converter circuit, it can be detected as soon as possible and protective measures can be taken in a timely manner to prevent damage to the DCDC converter circuit and the DC-AC converter circuit, thereby further improving the safety of the energy storage system. Among them, the specific implementation structure of the negative differential mode current detection unit can be any structure that can realize the negative differential mode current detection function known to those skilled in the art, such as but not limited to any one of a shunt and a current transformer, and is not specifically limited here.

[0016] Regarding the common-mode current detection unit: one end of the common-mode current detection unit is connected to the positive input end of the DCDC converter circuit, and the other end of the common-mode current detection unit is connected to the negative input end of the DCDC converter circuit. In this case, the common-mode current detection unit detects the common-mode current between the positive input end and the negative input end of the DCDC converter circuit. Since the positive input end of the DCDC converter circuit is connected to the positive output end of the battery cluster, and the negative input end of the DCDC converter circuit is connected to the negative output end of the battery cluster, the common-mode current between the positive input end and the negative input end of the DCDC converter circuit detected by the common-mode current detection unit can be regarded as the common-mode current between the positive output end and the negative output end of the battery cluster. Therefore, when arcing occurs at the positive output end and the negative output end of the battery cluster, it can be detected as early as possible, and protective measures can be taken in time to prevent damage to the battery cluster and the DCDC converter circuit, thereby further improving the safety of the energy storage system. Alternatively, one end of the common-mode current detection unit is connected to the positive output end of the DCDC conversion circuit, and the other end of the common-mode current detection unit is connected to the negative output end of the DCDC conversion circuit. In this case, the common-mode current detection unit detects the common-mode current between the positive output end and the negative output end of the DCDC conversion circuit. Thus, when arcing occurs at the positive output end and the negative output end of the DCDC conversion circuit, it can be detected as early as possible and protective measures can be taken in time to avoid damage to the DCDC conversion circuit and the DCAC conversion circuit, thereby further improving the safety of the energy storage system. The specific implementation structure of the common-mode current detection unit can be any structure that can realize the common-mode current detection function known to those skilled in the art, such as but not limited to a residual current protector, a current transformer, or a Hall sensor, and is not specifically limited here.

[0017] Optionally, when controlling the disconnection of the path between the battery cluster and the output end of the energy storage system, the controller can be specifically configured to: when the frequency domain component of the common-mode current is greater than a first preset amplitude, control the DCDC conversion circuit to not output DC power. Thus, even if the battery cluster outputs electrical energy to the DCDC conversion circuit, because the DCDC conversion circuit does not output DC power externally, the electrical energy output by the battery cluster will not be output through the DCDC conversion circuit, thereby disconnecting the path between the battery cluster and the output end of the energy storage system. The DCDC conversion circuit may include multiple transistors, and the controller can prevent the DCDC conversion circuit from outputting DC power by controlling the disconnection of transistors among the multiple transistors that are configured to output DC power externally. The connection relationship and configuration of the transistors can be determined based on actual needs and are not limited herein.

[0018] Of course, when the energy storage system also includes a DCAC conversion circuit, and the positive input terminal of the DCAC conversion circuit is connected to the positive output terminal of the DCDC conversion circuit, and the negative input terminal of the DCAC conversion circuit is connected to the negative output terminal of the DCDC conversion circuit, the controller can also be specifically configured to: when the frequency domain component of the common-mode current is greater than a first preset amplitude, control the DCAC conversion circuit to not output AC power. In this way, even if the battery cluster outputs electrical energy to the DCDC conversion circuit, and the DCDC conversion circuit outputs electrical energy to the DCAC conversion circuit, because the DCAC conversion circuit does not output AC power, the electrical energy output by the battery cluster will not be output through the DCAC conversion circuit, thereby disconnecting the path between the battery cluster and the output terminal of the energy storage system. The DCAC conversion circuit can also include multiple transistors. The controller can prevent the DCAC conversion circuit from outputting AC power by controlling the transistors among the multiple transistors that are configured to output AC power to disconnect. The connection relationship and configuration of the transistors can be determined based on actual needs and are not limited herein.

[0019] Optionally, in addition to the differential-mode current detection unit and the common-mode current detection unit, the detection device may also include a voltage detection unit, wherein a first end of the voltage detection unit is connected to the positive output terminal of the battery cluster, a second end is connected to the negative output terminal of the battery cluster, and a third end is connected to the controller. In this case, the voltage detection unit is configured to collect the voltage between the positive and negative output terminals of the battery cluster and transmit it to the controller. Alternatively, the first end of the voltage detection unit is connected to the positive output terminal of the DC-DC converter circuit, a second end is connected to the negative output terminal of the DC-DC converter circuit, and a third end is connected to the controller. In this case, the voltage detection unit is configured to collect the voltage between the positive and negative output terminals of the DC-DC converter circuit and transmit it to the controller. In this case, the controller may also be configured to report the voltage in response to a reporting instruction. In other words, the controller may store the received voltage and, upon receiving a reporting instruction from the server, report the voltage to the server. This allows the server to monitor and analyze the operating status of the energy storage system and serve as a data reference during maintenance and repair of the energy storage system, thereby improving maintenance and repair efficiency. It should be understood that the specific implementation structure of the voltage detection unit can be any structure known to those skilled in the art that can implement the voltage detection function, such as but not limited to a voltage divider resistor, and is not specifically limited here.

[0020] Optionally, the energy storage system may further include: a first switch and a second switch, wherein one end of the first switch is connected to the positive output end of the battery cluster, and the other end of the first switch is connected to the positive input end of the DCAC conversion circuit; one end of the second switch is connected to the negative output end of the battery cluster, and the other end of the second switch is connected to the negative input end of the DCAC conversion circuit; the controller may further be configured to: when the frequency domain component of the common-mode current is greater than a first preset amplitude, control the first switch and the second switch to be disconnected, thereby cutting off the conductive path between the positive output end of the battery cluster and the positive input end of the DCAC conversion circuit, and cutting off the conductive path between the negative output end of the battery cluster and the negative input end of the DCAC conversion circuit, thereby effectively cutting off the power supply path for the battery cluster to output electrical energy, disconnecting the battery cluster from the power supply path, suppressing the continued generation of arcing, and further improving the safety of the energy storage system.

[0021] The specific setting position of the first switch may include: one end of the first switch is connected to the positive output end of the battery cluster, and the other end of the first switch is connected to the positive input end of the DCDC conversion circuit. In this way, when the first switch is disconnected, the conductive path between the positive output end of the battery cluster and the positive input end of the DCDC conversion circuit can be cut off. When the first switch is closed, the positive output end of the battery cluster and the positive input end of the DCDC conversion circuit can be connected. Therefore, the on-off of the first switch can control the connection between the positive output end of the battery cluster and the positive input end of the DCDC conversion circuit, so that the connection between the positive output end of the battery cluster and the positive input end of the DCDC conversion circuit can be promptly disconnected when arcing occurs. Alternatively, one end of the first switch is connected to the positive output of the DCDC converter circuit, and the other end of the first switch is connected to the positive input of the DCAC converter circuit. In this way, when the first switch is opened, the conductive path between the positive output of the DCDC converter circuit and the positive input of the DCAC converter circuit can be cut off. When the first switch is closed, the positive output of the DCDC converter circuit and the positive input of the DCAC converter circuit can be connected. Therefore, the on-off switching of the first switch can control the connection between the positive output of the DCDC converter circuit and the positive input of the DCAC converter circuit, thereby promptly disconnecting the positive output of the DCDC converter circuit and the positive input of the DCAC converter circuit when arcing occurs.

[0022] The specific setting position of the second switch may include: one end of the second switch is connected to the negative output terminal of the battery cluster, and the other end of the first switch is connected to the negative input terminal of the DCDC converter circuit. In this case, when the second switch is opened, the conductive path between the negative output terminal of the battery cluster and the negative input terminal of the DCDC converter circuit can be cut off. When the second switch is closed, the negative output terminal of the battery cluster and the negative input terminal of the DCDC converter circuit can be connected. Therefore, the on and off of the second switch can control the connection between the negative output terminal of the battery cluster and the negative input terminal of the DCDC converter circuit, so that the connection between the negative output terminal of the battery cluster and the negative input terminal of the DCDC converter circuit can be promptly disconnected when arcing occurs. Alternatively, one end of the second switch is connected to the negative output terminal of the DCDC converter circuit, and the other end of the second switch is connected to the negative input terminal of the DCAC converter circuit. In this case, when the second switch is opened, the conductive path between the negative output terminal of the DCDC converter circuit and the negative input terminal of the DCAC converter circuit can be cut off. When the second switch is closed, the negative output terminal of the DCDC converter circuit and the negative input terminal of the DCAC converter circuit can be connected. Therefore, the on-off switching of the second switch can control the connection between the negative output terminal of the DCDC converter circuit and the negative input terminal of the DCAC converter circuit, so that the connection between the negative output terminal of the DCDC converter circuit and the negative input terminal of the DCAC converter circuit can be promptly disconnected when arcing occurs.

[0023] Based on this, and based on the position settings of the first switch and the second switch, when arcing occurs, the connection between the output end of the battery cluster and the input end of the DCDC conversion circuit can be promptly disconnected through the first switch and the second switch, thereby disconnecting both output ends of the battery cluster from the conductive path. Alternatively, when arcing occurs, the connection between the output end of the DCDC conversion circuit and the input end of the DCAC conversion circuit can be promptly disconnected through the first switch and the second switch, thereby disconnecting both output ends of the DCDC conversion circuit from the conductive path. Thus, the power supply path for the battery cluster to output electrical energy can be effectively cut off, thereby suppressing the continued occurrence of arcing.

[0024] Furthermore, the first switch may be at least one of a relay and a contactor, such as a relay, a contactor, or both. Similarly, the second switch may also be at least one of a relay and a contactor, such as a relay, a contactor, or both.

[0025] Optionally, the energy storage system may further include a first protector and a second protector. One end of the first protector is connected to the positive output of the battery cluster, and the other end of the first protector is connected to the positive input of the DC-AC converter circuit. The first protector is disconnected when the current in the circuit connected to the first protector exceeds a first preset current, and otherwise remains closed. One end of the second protector is connected to the negative output of the battery cluster, and the other end of the second protector is connected to the negative input of the DC-AC converter circuit. The second protector is disconnected when the current in the circuit connected to the second protector exceeds a second preset current, and otherwise remains closed. In this way, the first and second protectors can disconnect the paths they control, preventing damage to the battery cluster, DC-DC converter circuit, and DC-AC converter circuit when excessive current occurs, thereby improving the reliability of the energy storage system. It should be understood that the first and second preset currents can be set based on the maximum currents that the battery cluster, DC-DC converter circuit, and DC-AC converter circuit can withstand to prevent damage to the battery cluster, DC-DC converter circuit, and DC-AC converter circuit. The specific values ​​are not limited herein.

[0026] The specific setting position of the first protector may include: one end of the first protector is connected to the positive output end of the battery cluster, and the other end of the first protector is connected to the positive input end of the DCDC conversion circuit. In this case, when the first protector is disconnected, the conductive path between the positive output end of the battery cluster and the positive input end of the DCDC conversion circuit can be cut off. When the first protector is closed, the positive output end of the battery cluster and the positive input end of the DCDC conversion circuit can be connected. Therefore, the on-off switching of the first protector can control the on-off switching between the positive output end of the battery cluster and the positive input end of the DCDC conversion circuit. Therefore, when the current in the circuit between the positive output end of the battery cluster and the positive input end of the DCDC conversion circuit exceeds a first preset current, the positive output end of the battery cluster and the positive input end of the DCDC conversion circuit are promptly disconnected, thereby preventing damage to the battery cluster and the DCDC conversion circuit. Alternatively, one end of the first protector is connected to the positive output of the DCDC converter circuit, and the other end of the first protector is connected to the positive input of the DCAC converter circuit. In this case, when the first protector is disconnected, the conductive path between the positive output of the DCDC converter circuit and the positive input of the DCAC converter circuit is cut off. When the first protector is closed, the positive output of the DCDC converter circuit and the positive input of the DCAC converter circuit are connected. Therefore, the on / off switching of the first protector can control the connection between the positive output of the DCDC converter circuit and the positive input of the DCAC converter circuit. When the current in the line between the positive output of the DCDC converter circuit and the positive input of the DCAC converter circuit of the battery cluster exceeds a first preset current, the positive output of the DCDC converter circuit and the positive input of the DCAC converter circuit are promptly disconnected, thereby preventing damage to the DCDC converter circuit and the DCAC converter circuit.

[0027] The specific location of the second protector may include: one end of the second protector is connected to the negative output terminal of the battery cluster, and the other end of the second protector is connected to the negative input terminal of the DCDC converter circuit. In this case, when the second protector is disconnected, the conductive path between the negative output terminal of the battery cluster and the negative input terminal of the DCDC converter circuit can be cut off. When the second protector is closed, the negative output terminal of the battery cluster and the negative input terminal of the DCDC converter circuit can be connected. Therefore, the on-off switching of the second protector can control the connection between the negative output terminal of the battery cluster and the negative input terminal of the DCDC converter circuit. When the current in the circuit between the negative output terminal of the battery cluster and the negative input terminal of the DCDC converter circuit exceeds a second preset current, the negative output terminal of the battery cluster and the negative input terminal of the DCDC converter circuit are promptly disconnected, thereby preventing damage to the battery cluster and the DCDC converter circuit. Alternatively, one end of the second protector is connected to the negative output terminal of the DCDC converter circuit, and the other end of the second protector is connected to the negative input terminal of the DCAC converter circuit. In this case, when the second protector is disconnected, the conductive path between the negative output terminal of the DCDC converter circuit and the negative input terminal of the DCAC converter circuit is cut off. When the second protector is closed, the negative output terminal of the DCDC converter circuit and the negative input terminal of the DCAC converter circuit are connected. Therefore, the on / off switching of the second protector can control the connection between the negative output terminal of the DCDC converter circuit and the negative input terminal of the DCAC converter circuit. When the current in the line between the negative output terminal of the DCDC converter circuit and the negative input terminal of the DCAC converter circuit of the battery cluster exceeds a second preset current, the negative output terminal of the DCDC converter circuit and the negative input terminal of the DCAC converter circuit are promptly disconnected, thereby preventing damage to the DCDC converter circuit and the DCAC converter circuit.

[0028] Furthermore, the first protector may be at least one of a fuse and an air switch, such as a fuse, an air switch, or both. Similarly, the second protector may also be at least one of a fuse and an air switch, such as a fuse, an air switch, or both.

[0029] Furthermore, if the energy storage system is simultaneously provided with a first switch, a second switch, a first protector, and a second protector, the first switch and the first protector may be connected in series between the positive output terminal of the battery cluster and the positive input terminal of the DCDC conversion circuit, or between the positive output terminal of the DCDC conversion circuit and the positive input terminal of the DCAC conversion circuit; similarly, the second switch and the second protector may be connected in series between the negative output terminal of the battery cluster and the negative input terminal of the DCDC conversion circuit, or between the negative output terminal of the DCDC conversion circuit and the negative input terminal of the DCAC conversion circuit. Furthermore, when the frequency domain component is greater than the second preset amplitude, the corresponding positive differential mode current is generally smaller than the first preset current; when the frequency domain component is greater than the second preset amplitude, the corresponding negative differential mode current is generally smaller than the second preset current; and when the frequency domain component is greater than the first preset amplitude, the corresponding common mode current is generally smaller than the first preset current and the second preset current. Therefore, when it is necessary to control the disconnection of the path between the battery cluster and the output end of the energy storage system, the current at the positive output end of the battery cluster or the positive output end of the DCDC conversion circuit is likely not to have reached the first preset current, and the current at the negative output end of the battery cluster or the negative output end of the DCDC conversion circuit is likely not to have reached the second preset current. Therefore, before the path between the battery cluster and the output end of the energy storage system is disconnected, the first protector and the second protector are likely not to have disconnected their respective lines. Therefore, the controller can control the first switch and the second switch to disconnect the path for the battery cluster to supply power to the outside, disconnect the battery cluster from the power supply path, and suppress the continued generation of arcing.

[0030] During the energy storage system's startup, if the battery cluster is not controlled to prevent it from outputting electrical energy, the energy storage system will operate normally. The electrical energy provided by the battery cluster is processed in turn by the DCDC conversion circuit and the DCAC conversion circuit before being output. During normal operation, if for some reason the current at the positive output terminal of the battery cluster or the positive output terminal of the DCDC conversion circuit exceeds a first preset current, the first protector disconnects the associated circuit. If the current at the negative output terminal of the battery cluster or the negative output terminal of the DCDC conversion circuit exceeds a second preset current, the second protector disconnects the associated circuit. This protects the energy storage system during operation, improving its safety and reliability.

[0031] In a second aspect, embodiments of the present application further provide a battery cluster, which may include: one or more battery modules, a common-mode current detection unit, and a controller. The one or more battery modules are connected in series, and each of the series-connected battery modules may be referred to as a module assembly. One end of the common-mode current detection unit is connected to the positive output terminal of the one or more battery modules (i.e., the module assembly), and the other end of the common-mode current detection unit is connected to the negative output terminal of the one or more battery modules (i.e., the module assembly). The common-mode current detection unit is configured to detect the common-mode current in the connected circuit. The controller is configured to control the battery cluster to not output power when a frequency domain component of the common-mode current exceeds a first preset amplitude. In this manner, the controller can determine the frequency domain component of the common-mode current, and when the frequency domain component of the common-mode current exceeds the first preset amplitude, the controller can control the module assembly to not output power, thereby achieving arc extinguishing or protective action. This improves the accuracy and effectiveness of arc detection, reduces detection errors, and allows timely implementation of arc extinguishing measures when arcing occurs, thereby improving the safety of the battery cluster.

[0032] Optionally, the specific implementation structure of the common-mode current detection unit can be any structure known to those skilled in the art that can implement the common-mode current detection function, such as but not limited to a residual current protector, a current transformer or a Hall sensor, and is not specifically limited here.

[0033] Optionally, the battery cluster may further include a differential-mode current detection unit connected to the positive or negative output terminals of one or more battery modules (i.e., a module combination) and configured to detect differential-mode current in the connected circuit. The controller is further configured to control the battery cluster to not output electrical energy if the frequency domain component of the differential-mode current exceeds a second predetermined amplitude. This allows detection of not only differential-mode current but also common-mode current, enabling detection of multiple currents. This allows for determination of arcing from multiple perspectives, improving the accuracy and effectiveness of arcing detection, reducing detection errors, and enabling timely implementation of arc extinguishing measures when arcing occurs, thereby improving the safety of the battery cluster.

[0034] The differential-mode current detection unit may include at least one of a positive differential-mode current detection unit and a negative differential-mode current detection unit. The positive differential-mode current detection unit is connected to the positive output terminal of the module assembly and can detect the positive differential-mode current at the positive output terminal of the module assembly and transmit it to the controller. The negative differential-mode current detection unit is connected to the negative output terminal of the module assembly and can detect the negative differential-mode current at the negative output terminal of the module assembly and transmit it to the controller. The controller is specifically configured to control the module assembly to not output electrical energy, thereby achieving arc extinguishing or protective action, when the frequency domain component of the positive differential-mode current exceeds a second preset amplitude, the frequency domain component of the negative differential-mode current exceeds a second preset amplitude, or the frequency domain component of the common-mode current exceeds a first preset amplitude. It should be understood that the specific implementation structure of the positive differential-mode current detection unit can be any structure known to those skilled in the art that can achieve the positive differential-mode current detection function, such as, but not limited to, a shunt or a current transformer, and is not specifically limited here. The specific implementation structure of the negative differential mode current detection unit can be any structure known to those skilled in the art that can realize the negative differential mode current detection function, such as but not limited to any one of a shunt and a current transformer, and is not specifically limited here.

[0035] Optionally, the battery cluster may further include a first switch and a second switch; one end of the first switch is connected to the positive output terminal of one or more battery modules (i.e., the module combination), and the other end of the first switch is connected to the positive output terminal of the battery cluster; one end of the second switch is connected to the negative output terminal of one or more battery modules (i.e., the module combination), and the other end of the second switch is connected to the negative output terminal of the battery cluster; the controller is configured to control the first switch and the second switch to be disconnected when the frequency domain component of the common-mode current is greater than a first preset amplitude. In this way, when the controller determines that the battery cluster needs to be controlled not to output electrical energy, it controls the first switch and the second switch to be disconnected, cutting off the path controlled by the first switch and the path controlled by the second switch, thereby effectively cutting off the path for the battery cluster to supply power to the outside, disconnecting the module combination from the power supply path, suppressing the continued generation of arcing, and further improving the safety of the energy storage system. It should be understood that, in order to be able to distinguish it from the first switch arranged outside the battery cluster, the first switch arranged inside the battery cluster can also be referred to as the third switch, so the third switch mentioned in this application refers to the first switch arranged inside the battery cluster; similarly, in order to be able to distinguish it from the second switch arranged outside the battery cluster, the second switch arranged inside the battery cluster can also be referred to as the fourth switch, so the fourth switch mentioned in this application refers to the second switch arranged inside the battery cluster.

[0036] Of course, a battery cluster may or may not have a protector. When a protector is provided, the battery cluster may also include a third protector and a fourth protector. One end of the third protector is connected to the positive output terminal of the module assembly, and the other end is connected to the positive output terminal of the battery cluster. When the third protector is disconnected, it can cut off the conductive path between the positive output terminal of the module assembly and the positive output terminal of the battery cluster. When the third protector is closed, it can connect the positive output terminal of the module assembly and the positive output terminal of the battery cluster. One end of the fourth protector is connected to the negative output terminal of the module assembly, and the other end is connected to the negative output terminal of the battery cluster. When the fourth protector is disconnected, it can cut off the conductive path between the negative output terminal of the module assembly and the negative output terminal of the battery cluster. When the fourth protector is closed, it can connect the negative output terminal of the module assembly and the negative output terminal of the battery cluster. In this way, the third protector disconnects when the current in the circuit connected to it exceeds a third preset current; otherwise, it remains closed. The fourth protector disconnects when the current in the circuit connected to it exceeds a fourth preset current; otherwise, it remains closed. The third and fourth protectors can cut off their respective controlled pathways, preventing damage to the module assembly and battery cluster when excessive current flows, thereby improving the reliability of the energy storage system. It should be understood that the third and fourth preset currents can be set based on the maximum current that the module assembly and battery cluster can withstand to prevent damage to the battery cluster. The specific values ​​are not limited herein.

[0037] Furthermore, when a third switch, a fourth switch, a third protector and a fourth protector are provided in the battery cluster, the third switch and the third protector can be connected in series between the positive output end of the module combination and the positive output end of the battery cluster, and the fourth switch and the fourth protector can be connected in series between the negative output end of the module combination and the negative output end of the battery cluster.

[0038] Optionally, when a controller is provided inside the battery cluster and a controller is also provided outside the battery cluster, the two controllers may be the same controller or different controllers. The specific design may be made according to actual conditions and is not limited here.

[0039] It should be understood that the implementation principle of the positive differential mode current detection unit, the implementation principle of the negative differential mode current detection unit, the implementation principle of the common mode current detection unit, and the implementation methods of each switch and each protector in this embodiment are basically the same as the implementation principle of the positive differential mode current detection unit, the implementation principle of the negative differential mode current detection unit, the implementation principle of the common mode current detection unit, and the implementation methods of each switch and each protector introduced in the first aspect above. For details, please refer to the relevant introduction in the first aspect and any embodiment of the first aspect, and the repetitive parts will not be repeated.

[0040] In a third aspect, embodiments of the present application further provide an energy storage system, comprising: a battery cluster as described in the second aspect and any of the embodiments thereof, and a power conversion circuit, the power conversion circuit being electrically connected to the battery cluster; the power conversion circuit being configured to convert direct current (DC) power provided by the battery cluster into alternating current (AC) power for output, or to convert input AC power into DC power for output to the battery cluster. Thus, as the safety of the battery cluster is improved, the safety of the energy storage system can also be improved.

[0041] It should be understood that since the principle of solving the problem of the energy storage system is similar to the principle of solving the problem of the aforementioned battery cluster, the implementation and technical effects of the energy storage system can refer to the implementation and technical effects of the aforementioned battery cluster, and the repeated parts will not be repeated.

[0042] Fourthly, embodiments of the present application further provide a photovoltaic storage device, comprising: a photovoltaic power generation device, an inverter, and an energy storage system as described in the first aspect and any embodiment thereof, or an energy storage system as described in the third aspect and any embodiment thereof, wherein the inverter is connected to the photovoltaic power generation device and the energy storage system, respectively; the photovoltaic power generation device is configured to generate direct current (DC) electricity; and the inverter is configured to convert the DC electricity generated by the photovoltaic power generation device into AC electricity for transmission to the energy storage system. Thus, as the safety of the energy storage system is improved, the safety of the photovoltaic power generation device can also be improved.

[0043] It should be understood that since the principle of solving the problem by the photovoltaic storage device is similar to the principle of solving the problem by the aforementioned energy storage system, the implementation and technical effects of the photovoltaic storage device can refer to the implementation and technical effects of the aforementioned energy storage system, and the repeated parts will not be repeated. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG1 is a schematic structural diagram of an optical storage device provided in an embodiment of the present application;

[0045] FIG2 is a schematic structural diagram of an energy storage system provided in an embodiment of the present application;

[0046] FIG3 is a schematic structural diagram of another energy storage system provided in an embodiment of the present application;

[0047] FIG4 is a schematic structural diagram of another energy storage system provided in an embodiment of the present application;

[0048] FIG5 is a schematic structural diagram of another energy storage system provided in an embodiment of the present application;

[0049] FIG6 is a schematic structural diagram of another energy storage system provided in an embodiment of the present application;

[0050] FIG7 is a schematic structural diagram of another energy storage system provided in an embodiment of the present application;

[0051] FIG8 is a schematic structural diagram of another energy storage system provided in an embodiment of the present application;

[0052] FIG9 is a schematic structural diagram of another energy storage system provided in an embodiment of the present application;

[0053] FIG10 is a schematic structural diagram of another energy storage system provided in an embodiment of the present application;

[0054] FIG11 is a schematic structural diagram of another energy storage system provided in an embodiment of the present application;

[0055] FIG12 is a schematic structural diagram of another energy storage system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solutions and advantages of this application clearer, this application will be further described in detail below with reference to the accompanying drawings.

[0057] It should be noted that the same reference numerals in the drawings of this application represent the same or similar structures, and thus their repeated description will be omitted. The words expressing positions and directions described in this application are all explained using the drawings as examples, but they can be modified as needed, and such modifications are included in the scope of protection of this application. The drawings of this application are only for illustrating relative positional relationships and do not represent true proportions.

[0058] In order to facilitate understanding of the technical solution provided by the embodiments of the present application, its application scenario is first explained below.

[0059] The technical solution provided in the embodiments of the present application can be applied to photovoltaic storage devices. Figure 1 exemplifies a possible networking diagram of a photovoltaic storage device 100. As shown in Figure 1, the photovoltaic storage device 100 includes: a DC source 110 and a power converter 120. The DC source 110 includes: a photovoltaic power generation device 111 and a battery cluster 112. The power converter 120 includes: an inverter 121 and an energy storage converter 122. The inverter 121 is respectively connected to the photovoltaic power generation device 111, the AC power grid 200 and the energy storage converter 122. The energy storage converter 122 is also connected to the battery cluster 112. The photovoltaic power generation device 111 converts solar energy into direct current (DC) through the photovoltaic effect. The inverter 121 converts the DC output of the photovoltaic power generation device 111 into alternating current (AC), which is then transmitted to the AC grid 200 and the energy storage converter 122. The energy storage converter 122 converts the AC power from the AC grid 200 and the inverter 121 into DC power, which is then transmitted to the battery cluster 112 for storage. This allows for the storage of unstable electrical energy from the photovoltaic power generation device 111, while also allowing for the output of stable AC power to the AC grid 200 via the energy storage converter 122.

[0060] As shown in FIG1 , the energy storage system m0 may include a battery cluster 112 and an energy storage converter 122. The energy storage converter 122 may include a DC-DC conversion circuit and a DC-AC conversion circuit. One or more battery clusters may be provided, and one or more energy storage converters may be provided. When multiple battery clusters are provided, multiple energy storage converters may be provided, and the number of DC-DC conversion circuits and DC-AC conversion circuits provided is the same. The positive output of at least one battery cluster is connected to the positive input of a D-CDC conversion circuit, the negative output of at least one battery cluster is connected to the negative input of a D-CDC conversion circuit, the positive output of a D-CDC conversion circuit is connected to the positive input of a DC-AC conversion circuit, the negative output of a D-CDC conversion circuit is connected to the negative input of a DC-AC conversion circuit, and the output of a DC-AC conversion circuit is connected to the AC power grid. When multiple battery clusters are provided, a single energy storage converter may be provided (not shown). In this case, the positive output of each battery cluster is connected to the positive input of the DCDC conversion circuit, and the negative output of each battery cluster is connected to the negative input of the DCDC conversion circuit, so that the battery clusters are connected in parallel, and the positive output of the DCDC conversion circuit is connected to the positive input of the DCAC conversion circuit, the negative output of the DCDC conversion circuit is connected to the negative input of the DCAC conversion circuit, and the output of the DCAC conversion circuit is connected to the AC power grid.

[0061] As a product with bidirectional energy exchange, the energy storage system m0 can serve as a backup power source, smooth the power generation side, and achieve peak load shifting and valley filling on the user side. As an energy source, the electrical safety of the energy storage system m0 is extremely important. As its operating time increases, faults such as poor contact, aging of components or insulation layers, and leakage may occur within the energy storage system m0, increasing the likelihood of arcing. The sparks and high temperatures caused by arcing can easily cause fires within the energy storage system m0, significantly reducing its safety. In electrical engineering, when the voltage between two conductors breaks through the air layer to form an arc, the air generates a large number of electrons, rapidly increasing its conductivity. Even if the distance between the two conductors continues to increase, the arc cannot be extinguished. This phenomenon is called arcing.

[0062] Based on this, the embodiments of the present application provide an energy storage system and a photovoltaic storage device for effectively and accurately detecting arcing in the energy storage system and improving the safety of the energy storage system.

[0063] The following describes an energy storage system using as an example a case where the positive output of a battery cluster is connected to the positive input of a DCDC conversion circuit, the negative output of a battery cluster is connected to the negative input of a DCDC conversion circuit, the positive output of a DCDC conversion circuit is connected to the positive input of a DC-AC conversion circuit, and the negative output of a DCDC conversion circuit is connected to the negative input of a DC-AC conversion circuit.

[0064] FIG2 is a schematic diagram illustrating the structure of an energy storage system m0 provided in the present application. As shown in FIG2 , the energy storage system may include: a battery cluster 112, a DCDC conversion circuit 1221, and a DCAC conversion circuit 1222. The positive input terminal n3 of the DCDC conversion circuit 1221 is connected to the positive output terminal n1 of the battery cluster 112, and the negative input terminal n4 of the DCDC conversion circuit 1221 is connected to the negative output terminal n2 of the battery cluster 112; the positive output terminal n5 of the DCDC conversion circuit 1221 is connected to the positive input terminal n7 of the DCAC conversion circuit 1222, and the negative output terminal n6 of the DCDC conversion circuit 1221 is connected to the negative input terminal n8 of the DCAC conversion circuit 1222.

[0065] The energy storage system may further include a first controller 141 and a first detection device 142. The first detection device 142 includes: a first common-mode current detection unit 1422; as shown in (a) of FIG2 , a first end of the first common-mode current detection unit 1422 is connected to the positive output terminal n1 of the battery cluster 112, a second end of the first common-mode current detection unit 1422 is connected to the negative output terminal n2 of the battery cluster 112, and a third end of the first common-mode current detection unit 1422 is connected to the first controller 141. The first common-mode current detection unit 1422 can detect the common-mode current between the positive output terminal n1 of the battery cluster 112 and the negative output terminal n2 of the battery cluster 112 and transmit it to the first controller 141, so that when an arc occurs between the positive output terminal n1 of the battery cluster 112 and the negative output terminal n2 of the battery cluster 112, the common-mode current can be detected. 2 (b), a first end of the first common-mode current detection unit 1422 is connected to the positive output terminal n5 of the DCDC conversion circuit 1221, a second end of the first common-mode current detection unit 1422 is connected to the negative output terminal n6 of the DCDC conversion circuit 1221, and a third end of the first common-mode current detection unit 1422 is connected to the first controller 141. The first common-mode current detection unit 1422 can detect the common-mode current between the positive output terminal n5 of the DCDC conversion circuit 1221 and the negative output terminal n6 of the DCDC conversion circuit 1221 and transmit it to the first controller 141, so that when arcing occurs between the positive output terminal n5 of the DCDC conversion circuit 1221 and the negative output terminal n6 of the DCDC conversion circuit 1221, it can be detected as early as possible.

[0066] In this way, the first controller 141 analyzes the common-mode current. Since the current has multiple frequency domain components, each frequency domain component in the common-mode current can be determined. Since the current when arcing occurs has different components in different frequency domains, the components in each frequency domain vary greatly, and some frequency domain components may be large while others are small, while the current when arcing does not occur has the characteristics that all components in different frequency domains are zero and no large frequency domain components exist, each determined frequency domain component can be analyzed. If a frequency domain component is greater than a first preset amplitude, it indicates that a large frequency domain component exists in the common-mode current. In this case, it can be determined that the common-mode current is the current when arcing occurs, and thus it can be determined that an arcing phenomenon has occurred. This improves the accuracy and effectiveness of arcing phenomenon detection and reduces detection errors. In addition, the first controller 141 can control the path between the battery cluster 112 and the output terminal Vt of the energy storage system to disconnect, thereby achieving arc extinguishing or protective action. Therefore, arc extinguishing measures can be taken in a timely manner when an arcing phenomenon occurs, thereby improving the safety of the energy storage system.

[0067] The first preset amplitude may be determined based on the frequency domain component of the current corresponding to the arcing phenomenon, so as to avoid and eliminate the arcing phenomenon. The specific value is not limited here.

[0068] Furthermore, the specific implementation structure of the first common-mode current detection unit 1422 can be any structure known to those skilled in the art that can implement the common-mode current detection function, such as but not limited to a residual current protector, a current transformer or a Hall sensor, and is not specifically limited here.

[0069] Furthermore, when controlling the path between the battery cluster 112 and the output terminal Vt of the energy storage system to be disconnected, at least one of the following may be included, but is not limited to: the first controller 141 controls the DC-to-DC converter circuit 1221 to not output direct current (DC), or the first controller 141 controls the DC-to-AC converter circuit 1222 to not output alternating current (AC). Optionally, the DC-to-DC converter circuit 1221 may include multiple transistors, and the first controller 141 controls the DC-to-AC converter circuit 1222 to not output DC by controlling the transistors that output DC power to be disconnected. The connection relationship and configuration of the transistors can be determined based on practical needs and are not limited herein. Similarly, the DC-to-AC converter circuit 1222 may also include multiple transistors, and the first controller 141 controls the DC-to-AC converter circuit 1222 to not output AC by controlling the transistors that output AC power to be disconnected. The connection relationship and configuration of the transistors can be determined based on practical needs and are not limited herein.

[0070] Figure 3 is a schematic structural diagram of the energy storage system provided in the present application. Referring to Figure 3, the structure of the energy storage system in this embodiment is basically similar to the structure of the energy storage system introduced in the first embodiment shown in Figure 2 above, except that: the first detection device 142 includes a first positive differential mode current detection unit 1421 and a first common mode current detection unit 1422. For example, as shown in (a) of FIG3 , the first positive differential-mode current detection unit 1421 is connected to the positive output terminal n1 of the battery cluster 112 and the first controller 141, respectively. The first positive differential-mode current detection unit 1421 can detect the positive differential-mode current of the positive output terminal n1 of the battery cluster 112 and transmit it to the first controller 141, so that when an arcing phenomenon occurs at the positive output terminal n1 of the battery cluster 112, it can be detected as early as possible; or, as shown in (b) and (c) of FIG3 , the first positive differential-mode current detection unit 1421 is connected to the positive output terminal n5 of the DCDC converter circuit 1221 and the first controller 141, respectively. The first positive differential-mode current detection unit 1421 can detect the positive differential-mode current of the positive output terminal n5 of the DCDC converter circuit 1221 and transmit it to the first controller 141, so that when an arcing phenomenon occurs at the positive output terminal n5 of the DCDC converter circuit 1221, it can be detected as early as possible.

[0071] In this way, the first positive differential-mode current detection unit 1421 and the first common-mode current detection unit 1422 can both be located between the battery cluster 112 and the DC-DC converter circuit 1221, as shown in FIG3(a). Alternatively, the first positive differential-mode current detection unit 1421 and the first common-mode current detection unit 1422 can both be located between the DC-DC converter circuit 1221 and the DC-AC converter circuit 1222, as shown in FIG3(c). Alternatively, one of the first positive differential-mode current detection unit 1421 and the first common-mode current detection unit 1422 can be located between the battery cluster 112 and the DC-DC converter circuit 1221, while the other can be located between the DC-DC converter circuit 1221 and the DC-AC converter circuit 1222, as shown, for example but not limited to, in FIG3(b). FIG3(b) is used herein as an example. The specific locations of the first positive differential-mode current detection unit 1421 and the first common-mode current detection unit 1422 can be determined based on actual circumstances and are not limited herein.

[0072] In this way, the first controller 141 can determine the frequency domain component of the received positive differential-mode current and the frequency domain component of the common-mode current. When the frequency domain component of the positive differential-mode current is greater than a second preset amplitude, or when the frequency domain component of the common-mode current is greater than a first preset amplitude, the first controller 141 can control the disconnection of the path between the battery cluster 112 and the output end of the energy storage system to extinguish an arc or perform a protective action. In this way, not only can positive differential-mode current be detected, but also common-mode current can be detected, enabling detection of multiple currents. This allows determining whether arcing is occurring from multiple perspectives, improving the accuracy and effectiveness of arcing detection, reducing detection errors, and enabling timely arc extinguishing measures when arcing occurs, thereby improving the safety of the energy storage system.

[0073] The second preset amplitude can be determined based on the frequency domain component of the current corresponding to the occurrence of arcing to avoid and eliminate the arcing phenomenon. The specific value is not limited herein. Furthermore, the specific implementation structure of the first positive differential mode current detection unit 1421 can be any structure well known to those skilled in the art that can implement the positive differential mode current detection function, such as, but not limited to, a shunt or a current transformer, and is not specifically limited herein.

[0074] It should be understood that in this embodiment, the implementation of other structures in the energy storage system except the first positive differential-mode current measuring unit is the same as the specific implementation of the corresponding structure introduced in the first embodiment shown in Figure 2 above. For details, please refer to the relevant introduction of the first embodiment shown in Figure 2 above, and the repeated parts will not be repeated.

[0075] Figure 4 is a schematic structural diagram of the energy storage system provided in the present application. Referring to Figure 4, the structure of the energy storage system in this embodiment is basically similar to the structure of the energy storage system introduced in the first embodiment shown in Figure 2 above, except that: the first detection device 142 includes a first negative differential mode current detection unit 1423 and a first common mode current detection unit 1422. For example, as shown in (a) of FIG4 , the first negative differential-mode current detection unit 1423 is connected to the negative output terminal n2 of the battery cluster 112 and the first controller 141, respectively. The first negative differential-mode current detection unit 1423 can detect the negative differential-mode current of the negative output terminal n2 of the battery cluster 112 and transmit it to the first controller 141, so that when an arcing phenomenon occurs at the negative output terminal n2 of the battery cluster 112, it can be detected as early as possible; or, as shown in (b) and (c) of FIG4 , the first negative differential-mode current detection unit 1423 is connected to the negative output terminal n6 of the DCDC conversion circuit 1221 and the first controller 141, respectively. The first negative differential-mode current detection unit 1423 can detect the negative differential-mode current of the negative output terminal n6 of the DCDC conversion circuit 1221 and transmit it to the first controller 141, so that when an arcing phenomenon occurs at the negative output terminal n6 of the DCDC conversion circuit 1221, it can be detected as early as possible. At this time, the first controller 141 can determine the frequency domain component of the received negative differential mode current, and when the frequency domain component of the negative differential mode current is greater than the second preset amplitude, or the frequency domain component of the common mode current is greater than the first preset amplitude, the first controller 141 can control the path between the battery cluster 112 and the output end of the energy storage system to be disconnected, thereby achieving arc extinguishing or protection action.

[0076] The first negative differential-mode current detection unit 1423 and the first common-mode current detection unit 1422 can both be located between the battery cluster 112 and the DC-DC converter circuit 1221, as shown in FIG4(a). Alternatively, the first negative differential-mode current detection unit 1423 and the first common-mode current detection unit 1422 can both be located between the DC-DC converter circuit 1221 and the DC-AC converter circuit 1222, as shown in FIG4(c). Alternatively, one of the first negative differential-mode current detection unit 1423 and the first common-mode current detection unit 1422 can be located between the battery cluster 112 and the DC-DC converter circuit 1221, while the other can be located between the DC-DC converter circuit 1221 and the DC-AC converter circuit 1222, as shown, for example but not limited to, in FIG4(b). FIG4(b) is used herein as an example. The specific locations of the first negative differential-mode current detection unit 1423 and the first common-mode current detection unit 1422 can be determined based on actual circumstances and are not limited herein.

[0077] Moreover, the specific implementation structure of the first negative differential mode current detection unit 1423 can be any structure known to those skilled in the art that can realize the negative differential mode current detection function, such as but not limited to any one of a shunt and a current transformer, and is not specifically limited here.

[0078] It should be understood that in this embodiment, the implementation of other structures in the energy storage system except the first negative differential-mode current measuring unit is the same as the specific implementation of the corresponding structure described in the first embodiment shown in FIG. 2 . For details, please refer to the relevant introduction of the first embodiment shown in FIG. 2 , and the repeated parts will not be repeated here.

[0079] FIG5 is a schematic diagram illustrating the structure of the energy storage system provided in the present application. As shown in FIG5 , the structure of the energy storage system in this embodiment is substantially similar to the structure of the energy storage system described in the first embodiment shown in FIG2 , with the difference being that the first detection device 142 includes a first positive differential-mode current detection unit 1421, a first negative differential-mode current detection unit 1423, and a first common-mode current detection unit 1422. Therefore, the first positive differential-mode current detection unit 1421 can detect the positive differential-mode current in the connected circuit, the first negative differential-mode current detection unit 1423 can detect the negative differential-mode current in the connected circuit, and the first common-mode current detection unit 1422 can also detect the common-mode current in the connected circuit. In this case, when any one of the following conditions is satisfied: the frequency domain component of the positive differential-mode current is greater than a second preset amplitude, the frequency domain component of the negative differential-mode current is greater than the second preset amplitude, and the frequency domain component of the common-mode current is greater than the first preset amplitude, the first controller 141 can control the path between the battery cluster 112 and the output end of the energy storage system to be disconnected, thereby achieving arc extinguishing or protective action. In this way, more current signals can be collected, and the positive differential mode current, negative differential mode current and common mode current can be combined to make a judgment, further improving the accuracy and effectiveness of arcing detection, further reducing detection errors, and thus further improving the safety of energy storage system use.

[0080] The first positive differential-mode current detection unit 1421, the first negative differential-mode current detection unit 1423, and the first common-mode current detection unit 1422 can all be disposed between the battery cluster 112 and the DC-DC converter circuit 1221, as shown in FIG5(a). Alternatively, the first positive differential-mode current detection unit 1421, the first negative differential-mode current detection unit 1423, and the first common-mode current detection unit 1422 can all be disposed between the DC-DC converter circuit 1221 and the DC-AC converter circuit 1222, as shown in FIG5(c). Alternatively, some of the first positive differential-mode current detection unit 1421, the first negative differential-mode current detection unit 1423, and the first common-mode current detection unit 1422 can be disposed between the battery cluster 112 and the DC-DC converter circuit 1221, while the remainder can be disposed between the DC-DC converter circuit 1221 and the DC-AC converter circuit 1222, as shown, for example but not limited to, in FIG5(b). FIG5(b) is used herein as an example. The specific locations of the first positive differential mode current detection unit 1421 , the first negative differential mode current detection unit 1423 and the first common mode current detection unit 1422 may be determined according to actual conditions and are not limited here.

[0081] It should be understood that in this embodiment, the specific implementation of the first common-mode current detection unit 1422 is the same as the specific implementation of the corresponding structure described in the first embodiment shown in FIG. 2 above. For details, please refer to the relevant introduction in the first embodiment shown in FIG. 2 above, and the repeated parts will not be repeated. The specific implementation of the first positive differential-mode current detection unit 1421 is the same as the specific implementation of the corresponding structure described in the second embodiment shown in FIG. 3 above. For details, please refer to the relevant introduction in the second embodiment shown in FIG. 3 above, and the repeated parts will not be repeated. The specific implementation of the first negative differential-mode current detection unit 1423 is the same as the specific implementation of the corresponding structure described in the third embodiment shown in FIG. 4 above. For details, please refer to the relevant introduction in the third embodiment shown in FIG. 4 above, and the repeated parts will not be repeated. In addition, the structure of the energy storage system in this embodiment is similar to the structure of the energy storage system described in the first embodiment shown in FIG. 2 above. Please also refer to the relevant introduction in the first embodiment shown in FIG. 2 above, and the repeated parts will not be repeated.

[0082] Figure 6 is a schematic structural diagram of the energy storage system provided in the present application. Referring to Figure 6, the structure of the energy storage system in this embodiment is basically similar to the structure of the energy storage system introduced in any one of the embodiments shown in Figures 2 to 5 above. The difference is that: on the basis of the energy storage system introduced in any one of the embodiments shown in Figures 2 to 5 above, the first detection device 142 also includes a voltage detection unit 1424. For example, as shown in (a) and (b) of FIG6 , the voltage detection unit 1424 is respectively connected to the first controller 141, the positive output terminal n1 of the battery cluster 112, and the negative output terminal n2 of the battery cluster 112. The voltage detection unit 1424 can collect the voltage between the positive output terminal n1 of the battery cluster 112 and the negative output terminal n2 of the battery cluster 112 and transmit the voltage to the first controller 141. Alternatively, as shown in (c) of FIG6 , the voltage detection unit 1424 is respectively connected to the first controller 141, the positive output terminal n5 of the DCDC conversion circuit 1221, and the negative output terminal n6 of the DCDC conversion circuit 1221. The voltage detection unit 1424 can collect the voltage between the positive output terminal n5 of the DCDC conversion circuit 1221 and the negative output terminal n6 of the DCDC conversion circuit 1221 and transmit the voltage to the first controller 141. At this time, the first controller 141 can store the received voltage and report the voltage to the server when receiving the reporting instruction issued by the server, so that the server can monitor and analyze the operating status of the energy storage system, and use it as a data reference when maintaining and repairing the energy storage system, thereby improving the efficiency of maintenance and repair.

[0083] When the first detection device 142 includes at least one of a first positive differential-mode current detection unit 1421 and a first negative differential-mode current detection unit 1423, as well as a first common-mode current detection unit 1422 and a voltage detection unit 1424, these detection units may be all disposed between the battery cluster 112 and the DCDC converter circuit 1221 (as shown in FIG6(a)), or all disposed between the DCDC converter circuit 1221 and the DC-AC converter circuit (as shown in FIG6(c)), or partially disposed between the battery cluster 112 and the DCDC converter circuit 1221 and the remaining portion between the DCDC converter circuit 1221 and the DC-AC converter circuit, as shown in FIG6(b), but the present invention is not limited to FIG6(b), and FIG6(b) is used herein as an example. In other words, the arrangement of these detection units may be determined according to actual circumstances and is not limited here.

[0084] Furthermore, the specific implementation structure of the voltage detection unit 1424 may be any structure known to those skilled in the art that can implement the voltage detection function, such as but not limited to a voltage divider resistor, which is not specifically limited here.

[0085] It should be understood that the structure of the energy storage system in this embodiment is similar to the structure of the energy storage system described in any of the embodiments shown in Figures 2 to 5 above. Please refer to the relevant introduction in any of the embodiments shown in Figures 2 to 5 above, and the repeated parts will not be repeated.

[0086] Figure 7 is a schematic structural diagram of the energy storage system provided in the present application. Referring to Figure 7, the structure of the energy storage system in this embodiment is basically similar to the structure of the energy storage system introduced in any of the embodiments shown in Figures 2 to 6 above. The difference is that: on the basis of the energy storage system introduced in any of the embodiments shown in Figures 2 to 6 above, the energy storage system further includes a first switch k1 and a second switch k2.

[0087] Regarding the first switch k1: one end of the first switch k1 is connected to the positive output terminal n1 of the battery cluster 112, and the other end of the first switch k1 is connected to the positive input terminal n3 of the DCDC converter circuit 1221. As shown in (a) and (b) of Figure 7, when the first switch k1 is open, it can cut off the conductive path between the positive output terminal n1 of the battery cluster 112 and the positive input terminal n3 of the DCDC converter circuit 1221. When the first switch k1 is closed, it can connect the positive output terminal n1 of the battery cluster 112 and the positive input terminal n3 of the DCDC converter circuit 1221. Therefore, the on-off switching of the first switch k1 can control the connection between the positive output terminal n1 of the battery cluster 112 and the positive input terminal n3 of the DCDC converter circuit 1221. Therefore, when arcing occurs, the connection between the positive output terminal n1 of the battery cluster 112 and the positive input terminal n3 of the DCDC converter circuit 1221 can be promptly disconnected, thereby cutting off the conductive path from the positive output terminal n1 of the battery cluster 112. Alternatively, one end of the first switch k1 is connected to the positive output terminal n5 of the DCDC converter circuit 1221, and the other end of the first switch k1 is connected to the positive input terminal n7 of the DCAC converter circuit 1222. As shown in FIG7(c), when the first switch k1 is disconnected, the conductive path between the positive output terminal n5 of the DCDC converter circuit 1221 and the positive input terminal n7 of the DCAC converter circuit 1222 is cut off. When the first switch k1 is closed, the positive output terminal n5 of the DCDC converter circuit 1221 and the positive input terminal n7 of the DCAC converter circuit 1222 are connected. Therefore, the on-off switching of the first switch k1 can control the connection between the positive output terminal n5 of the DCDC converter circuit 1221 and the positive input terminal n7 of the DCAC converter circuit 1222. Thus, when arcing occurs, the connection between the positive output terminal n5 of the DCDC converter circuit 1221 and the positive input terminal n7 of the DCAC converter circuit 1222 can be promptly disconnected. The first switch k1 may be at least one of a relay and a contactor, for example, the first switch k1 is a relay, or the first switch k1 is a contactor, or the first switch k1 is a relay and a contactor.

[0088] Regarding the second switch k2: one end of the second switch k2 is connected to the negative output terminal n2 of the battery cluster 112, and the other end of the second switch k2 is connected to the negative input terminal n4 of the DCDC converter circuit 1221, as shown in FIG7(a). When the second switch k2 is open, it can cut off the conductive path between the negative output terminal n2 of the battery cluster 112 and the negative input terminal n4 of the DCDC converter circuit 1221. When the second switch k2 is closed, it can connect the negative output terminal n2 of the battery cluster 112 and the negative input terminal n4 of the DCDC converter circuit 1221. Therefore, the on-off switching of the second switch k2 can control the connection between the negative output terminal n2 of the battery cluster 112 and the negative input terminal n4 of the DCDC converter circuit 1221. Thus, when arcing occurs, the connection between the negative output terminal n2 of the battery cluster 112 and the negative input terminal n4 of the DCDC converter circuit 1221 can be promptly disconnected. Alternatively, one end of the second switch k2 is connected to the negative output terminal n6 of the DCDC converter circuit 1221, and the other end of the second switch k2 is connected to the negative input terminal n8 of the DCAC converter circuit 1222. As shown in (b) and (c) of FIG7 , when the second switch k2 is open, the conductive path between the negative output terminal n6 of the DCDC converter circuit 1221 and the negative input terminal n8 of the DCAC converter circuit 1222 is cut off. When the second switch k2 is closed, the negative output terminal n6 of the DCDC converter circuit 1221 and the negative input terminal n8 of the DCAC converter circuit 1222 are connected. Therefore, the on-off switching of the second switch k2 can control the connection between the negative output terminal n6 of the DCDC converter circuit 1221 and the negative input terminal n8 of the DCAC converter circuit 1222. Thus, when arcing occurs, the connection between the negative output terminal n6 of the DCDC converter circuit 1221 and the negative input terminal n8 of the DCAC converter circuit 1222 can be promptly disconnected. The second switch k2 may also be at least one of a relay and a contactor, for example, the second switch k2 is a relay, or the second switch k2 is a contactor, or the second switch k2 is a relay and a contactor.

[0089] In this way, when the first controller 141 determines that it is necessary to cut off the path between the battery cluster 112 and the output end of the energy storage system, it controls the first switch k1 and the second switch k2 to be disconnected, cutting off the path controlled by the first switch k1 and the path controlled by the second switch k2, so as to effectively cut off the path between the battery cluster 112 and the output end of the energy storage system, disconnect the battery cluster 112 from the power supply path, suppress the continuous generation of arcing, and further improve the safety of the energy storage system.

[0090] Among them, the first switch k1 and the second switch k2 can be both arranged between the battery cluster 112 and the DCDC conversion circuit 1221, or both arranged between the DCDC conversion circuit 1221 and the DCAC conversion circuit 1222, or one of the switches can be arranged between the battery cluster 112 and the DCDC conversion circuit 1221, and the other can be arranged between the DCDC conversion circuit 1221 and the DCAC conversion circuit 1222. (a) to (c) in Figure 7 only show some of the configuration methods, but this does not mean that the configuration method of the first switch k1 and the second switch k2 is only as shown in (a) to (c) in Figure 7. Figures 7 (a) to (c) are used here as an example. The configuration method of the first switch k1 and the second switch k2 can be determined according to actual conditions and is not limited here.

[0091] It should be understood that the structure of the energy storage system in this embodiment is similar to the structure of the energy storage system described in any one of the embodiments shown in Figures 2 to 6 above. For reference, the relevant description in any one of the embodiments shown in Figures 2 to 6 above can also be made, and the repeated parts will not be repeated.

[0092] Figure 8 is a schematic structural diagram of the energy storage system provided in the present application. Referring to Figure 8, the structure of the energy storage system in this embodiment is basically similar to the structure of the energy storage system introduced in any one of the embodiments shown in Figures 2 to 7 above. The difference is that: on the basis of the energy storage system introduced in any one of the embodiments shown in Figures 2 to 7 above, the energy storage system further includes a first protector p1 and a second protector p2.

[0093] Regarding the first protector p1: one end of the first protector p1 is connected to the positive output terminal n1 of the battery cluster 112, and the other end of the first protector p1 is connected to the positive input terminal n3 of the DCDC converter circuit 1221. As shown in (a) of Figure 8, when the first protector p1 is disconnected, it can cut off the conductive path between the positive output terminal n1 of the battery cluster 112 and the positive input terminal n3 of the DCDC converter circuit 1221. When the first protector p1 is closed, it can connect the positive output terminal n1 of the battery cluster 112 and the positive input terminal n3 of the DCDC converter circuit 1221. Therefore, the on / off switching of the first protector p1 can control the on / off switching between the positive output terminal n1 of the battery cluster 112 and the positive input terminal n3 of the DCDC converter circuit 1221. Alternatively, one end of the first protector p1 is connected to the positive output terminal n5 of the DCDC converter circuit 1221, and the other end of the first protector p1 is connected to the positive input terminal n7 of the DCAC converter circuit 1222. As shown in (b) and (c) of FIG8 , when the first protector p1 is off, it can cut off the conductive path between the positive output terminal n5 of the DCDC converter circuit 1221 and the positive input terminal n7 of the DCAC converter circuit 1222. When the first protector p1 is on, it can connect the positive output terminal n5 of the DCDC converter circuit 1221 and the positive input terminal n7 of the DCAC converter circuit 1222. Therefore, the on / off switching of the first protector p1 can control the on / off switching between the positive output terminal n5 of the DCDC converter circuit 1221 and the positive input terminal n7 of the DCAC converter circuit 1222. Based on this, the first protector p1 is opened when the current in the circuit connected to it exceeds a first preset current, and otherwise remains closed. The first protector p1 may be at least one of a fuse and an air switch, for example, the first protector p1 is a fuse, or the first protector p1 is an air switch, or the first protector p1 is a fuse and an air switch.

[0094] Regarding the second protector p2: one end of the second protector p2 is connected to the negative output terminal n2 of the battery cluster 112, and the other end of the second protector p2 is connected to the negative input terminal n4 of the DCDC converter circuit 1221. As shown in (a) and (b) of Figure 8, when the second protector p2 is disconnected, it can cut off the conductive path between the negative output terminal n2 of the battery cluster 112 and the negative input terminal n4 of the DCDC converter circuit 1221. When the second protector p2 is closed, it can connect the negative output terminal n2 of the battery cluster 112 and the negative input terminal n4 of the DCDC converter circuit 1221. Therefore, the on and off of the second protector p2 can control the on and off between the negative output terminal n2 of the battery cluster 112 and the negative input terminal n4 of the DCDC converter circuit 1221. Alternatively, one end of the second protector p2 is connected to the negative output terminal n6 of the DCDC converter circuit 1221, and the other end of the second protector p2 is connected to the negative input terminal n8 of the DCAC converter circuit 1222. As shown in FIG8(c), when the second protector p2 is off, it can cut off the conductive path between the negative output terminal n6 of the DCDC converter circuit 1221 and the negative input terminal n8 of the DCAC converter circuit 1222. When the second protector p2 is on, it can connect the negative output terminal n6 of the DCDC converter circuit 1221 and the negative input terminal n8 of the DCAC converter circuit 1222. Therefore, the on-off switching of the second protector p2 can control the on-off switching between the negative output terminal n6 of the DCDC converter circuit 1221 and the negative input terminal n8 of the DCAC converter circuit 1222. Based on this, the second protector p2 is opened when the current in the circuit connected to it exceeds a second preset current, and otherwise remains closed. The second protector p2 may also be at least one of a fuse and an air switch, for example, the second protector p2 is a fuse, or the second protector p2 is an air switch, or the second protector p2 is a fuse and an air switch.

[0095] In this way, the first protector p1 and the second protector p2 can cut off the paths they control, preventing damage to the battery cluster 112, the DCDC converter circuit 1221, and the DCAC converter circuit 1222 when excessive current flows, thereby improving the reliability of the energy storage system. It should be understood that the first and second preset currents can be set based on the maximum currents that the battery cluster 112, the DCDC converter circuit 1221, and the DCAC converter circuit 1222 can withstand to prevent damage to the battery cluster 112, the DCDC converter circuit 1221, and the DCAC converter circuit 1222. The specific values ​​are not limited herein.

[0096] Furthermore, if the energy storage system is simultaneously provided with a first switch k1, a second switch k2, a first protector p1, and a second protector p2, the first switch k1 and the first protector p1 can be connected in series between the positive output terminal n1 of the battery cluster 112 and the positive input terminal n3 of the DCDC converter circuit 1221 (as shown in FIG8(a)), or connected in series between the positive output terminal n5 of the DCDC converter circuit 1221 and the positive input terminal n7 of the DC-AC converter circuit 1222 (as shown in FIG8(c)). Similarly, the second switch k2 and the second protector p2 can be connected in series between the negative output terminal n2 of the battery cluster 112 and the negative input terminal n4 of the DCDC converter circuit 1221 (as shown in FIG8(a)), or connected in series between the negative output terminal n6 of the DCDC converter circuit 1221 and the negative input terminal n8 of the DC-AC converter circuit 1222 (as shown in FIG8(c)). Furthermore, when the frequency domain component is greater than the first preset amplitude, the corresponding common-mode current is generally smaller than the first preset current and the second preset current. Therefore, when it is necessary to control the path between the battery cluster 112 and the output end of the energy storage system to be disconnected, the current at the positive output end n1 of the battery cluster 112 or the positive output end n5 of the DCDC conversion circuit 1221 may not have reached the first preset current, and the current at the negative output end n2 of the battery cluster 112 or the negative output end n6 of the DCDC conversion circuit 1221 may not have reached the second preset current. Therefore, before controlling the path between the battery cluster 112 and the output end of the energy storage system to be disconnected, the first protector p1 and the second protector p2 may not have disconnected their respective lines. Therefore, the first controller 141 can control the first switch k1 and the second switch k2 to disconnect the power supply path, thereby disconnecting the battery cluster 112 from the power supply path and suppressing the continued generation of arcing.

[0097] It should be understood that the structure of the energy storage system in this embodiment is similar to the structure of the energy storage system described in any of the embodiments shown in Figures 2 to 7 above. For details, reference can be made to the relevant descriptions of any of the embodiments shown in Figures 2 to 7 above, and any repetitions will not be repeated. Furthermore, to simplify the drawings, the output terminal Vt of the energy storage system is not shown in Figures 3 to 8 .

[0098] FIG9 is a schematic diagram illustrating the structure of an energy storage system provided in the present application. As shown in FIG9 , the energy storage system includes a battery cluster 112, a DC-DC conversion circuit 1221, and a DC-AC conversion circuit 1222. The battery cluster 112 includes one or more battery modules 112 a, each of which is connected in series. These battery modules 112 a can be considered as a whole and referred to as a module assembly 1121. The positive output terminal n9 of the module assembly 1121 is connected to the positive output terminal n1 of the battery cluster 112, and the negative output terminal n10 of the module assembly 1121 is connected to the negative output terminal n2 of the battery cluster 112.

[0099] The battery cluster 112 further includes: a second detection device 1122 and a second controller 1123 , wherein the second detection device 1122 includes a second common-mode current detection unit 1122 b ;

[0100] The first end of the second common-mode current detection unit 1122b is connected to the positive output terminal n9 of the module combination 1121, the second end of the second common-mode current detection unit 1122b is connected to the negative output terminal n10 of the module combination 1121, and the third end of the second common-mode current detection unit 1122b is connected to the second controller 1123; the second common-mode current detection unit 1122b can detect the common-mode current between the positive output terminal n9 of the module combination 1121 and the negative output terminal n10 of the module combination 1121 and transmit it to the second controller 1123.

[0101] In this way, second controller 1123 can determine the frequency domain component of the common-mode current. When the frequency domain component of the common-mode current exceeds a first predetermined amplitude, second controller 1123 can control module assembly 1121 to stop outputting power, thereby extinguishing the arc or performing a protective action. This improves the accuracy and effectiveness of arc detection, reduces detection errors, and allows timely implementation of arc extinguishing measures when an arc occurs, thereby improving the safety of battery cluster 112.

[0102] Among them, the specific implementation structure of the second common-mode current detection unit 1122b can be any structure that can realize the common-mode current detection function known to those skilled in the art, such as but not limited to a residual current protector, a current transformer or a Hall sensor, and is not specifically limited here.

[0103] Furthermore, the battery cluster 112 further includes a third switch k3 (corresponding to the first switch provided within the battery cluster 112 mentioned above) and a fourth switch k4 (corresponding to the second switch provided within the battery cluster 112 mentioned above). One end of the third switch k3 is connected to the positive output terminal n9 of the module assembly 1121, and the other end of the third switch k3 is connected to the positive output terminal n1 of the battery cluster 112. When the third switch k3 is open, it can cut off the conductive path between the positive output terminal n9 of the module assembly 1121 and the positive output terminal n1 of the battery cluster 112. When the third switch k3 is closed, it can connect the positive output terminal n9 of the module assembly 1121 and the positive output terminal n1 of the battery cluster 112. The third switch k3 can be at least one of a relay and a contactor, such as a relay, a contactor, or both.

[0104] One end of the fourth switch k4 is connected to the negative output terminal n10 of the module assembly 1121, and the other end of the fourth switch k4 is connected to the negative output terminal n2 of the battery cluster 112. When the fourth switch k4 is open, the conductive path between the negative output terminal n10 of the module assembly 1121 and the negative output terminal n2 of the battery cluster 112 is cut off. When the fourth switch k4 is closed, the negative output terminal n10 of the module assembly 1121 and the negative output terminal n2 of the battery cluster 112 are connected. The fourth switch k4 can be at least one of a relay and a contactor, such as a relay, a contactor, or both.

[0105] In this way, when the second controller 1123 determines that the battery cluster 112 needs to be controlled not to output electric energy to the outside, it controls the third switch k3 and the fourth switch k4 to be disconnected, cutting off the path controlled by the third switch k3 and the path controlled by the fourth switch k4, so as to effectively cut off the path for the battery cluster 112 to supply power to the outside, disconnect the module combination 1121 from the power supply path, suppress the continuous generation of arcing, and further improve the safety of the energy storage system.

[0106] Of course, a protector may be provided in the battery cluster 112, or a protector may be provided. When a protector is provided, a third protector p3 and a fourth protector p4 may also be provided in the battery cluster 112. One end of the third protector p3 is connected to the positive output terminal n9 of the module assembly 1121, and the other end of the third protector p3 is connected to the positive output terminal n1 of the battery cluster 112. When the third protector p3 is disconnected, the conductive path between the positive output terminal n9 of the module assembly 1121 and the positive output terminal n1 of the battery cluster 112 may be cut off. When the third protector p3 is closed, the positive output terminal n9 of the module assembly 1121 and the positive output terminal n1 of the battery cluster 112 may be connected. One end of the fourth protector p4 is connected to the negative output terminal n10 of the module assembly 1121, and the other end of the fourth protector p4 is connected to the negative output terminal n2 of the battery cluster 112. When the fourth protector p4 is disconnected, the conductive path between the negative output terminal n10 of the module assembly 1121 and the negative output terminal n2 of the battery cluster 112 is cut off. When the fourth protector p4 is closed, the negative output terminal n10 of the module assembly 1121 and the negative output terminal n2 of the battery cluster 112 are connected.

[0107] In this way, the third protector p3 disconnects when the current in the circuit connected to it exceeds a third preset current; otherwise, it remains closed. The fourth protector p4 disconnects when the current in the circuit connected to it exceeds a fourth preset current; otherwise, it remains closed. The third and fourth protectors p3 and p4 can cut off their respective controlled pathways, preventing damage to the module assembly 1121 and battery cluster 112 when excessive current occurs, thereby improving the reliability of the energy storage system. It should be understood that the third and fourth preset currents can be set based on the maximum current that the module assembly 1121 and battery cluster 112 can withstand to prevent damage to the battery cluster 112. The specific values ​​are not limited here.

[0108] Furthermore, when a third switch k3, a fourth switch k4, a third protector p3, and a fourth protector p4 are provided in the battery cluster, the third switch k3 and the third protector p3 can be connected in series between the positive output terminal n9 of the module combination 1121 and the positive output terminal n1 of the battery cluster 112, and the fourth switch k4 and the fourth protector p4 can be connected in series between the negative output terminal n10 of the module combination 1121 and the negative output terminal n2 of the battery cluster 112.

[0109] It should be understood that, in this embodiment, the principle of current detection by the second common-mode current detection unit 1122b is similar to the principle of current detection by the first common-mode current detection unit described in the first embodiment shown in FIG. 2 , and the manner of setting the first preset amplitude in this embodiment is similar to the manner of setting the first preset amplitude in the first embodiment shown in FIG. 2 . Furthermore, the connection relationship among the battery cluster 112, the DCDC conversion circuit 1221, and the DCAC conversion circuit 1222 in this embodiment is similar to the connection relationship among the battery cluster 112, the DCDC conversion circuit, and the DCAC conversion circuit described in the first embodiment shown in FIG. 2 . Therefore, for these details, reference may be made to the relevant description of the first embodiment shown in FIG. 2 , and any repetitions will be omitted.

[0110] FIG10 is a schematic diagram illustrating the structure of the energy storage system provided by the present application. Referring to FIG10 , the structure of the energy storage system in this embodiment is substantially similar to the structure of the energy storage system described in the eighth embodiment shown in FIG9 , with the difference being that the second detection device 1122 includes a second positive differential-mode current detection unit 1122a and a second common-mode current detection unit 1122b. For example, the second positive differential-mode current detection unit 1122a is connected to the positive output terminal n9 of the module assembly 1121 and the second controller 1123, respectively. The second positive differential-mode current detection unit 1122a can detect the positive differential-mode current at the positive output terminal n9 of the module assembly 1121 and transmit it to the second controller 1123.

[0111] In this way, second controller 1123 can determine the frequency domain component of the received positive differential-mode current and the frequency domain component of the common-mode current. When the frequency domain component of the positive differential-mode current is greater than a second preset amplitude, or when the frequency domain component of the common-mode current is greater than a first preset amplitude, second controller 1123 can control module assembly 1121 to not output power, thereby extinguishing the arc or performing a protective action. This allows detection of not only the positive differential-mode current but also the common-mode current, enabling detection of multiple currents. This allows for determination of arcing from multiple perspectives, improving the accuracy and effectiveness of arcing detection and reducing detection errors. When arcing occurs, timely arc extinguishing measures can be implemented, thereby improving the safety of battery cluster 112.

[0112] Among them, the specific implementation structure of the second positive differential mode current detection unit 1122a can be any structure that can realize the positive differential mode current detection function known to those skilled in the art, such as but not limited to any one of a shunt and a current transformer, and is not specifically limited here.

[0113] It should be understood that in this embodiment, the implementation of other structures in the energy storage system except the second common-mode current measuring unit 1122c is the same as the specific implementation of the corresponding structure described in the eighth embodiment shown in FIG9 above. For details, please refer to the relevant introduction of the eighth embodiment shown in FIG9 above, and the repeated parts will not be repeated.

[0114] FIG11 is a schematic diagram illustrating the structure of the energy storage system provided by the present application. Referring to FIG11 , the structure of the energy storage system in this embodiment is substantially similar to the structure of the energy storage system described in the eighth embodiment shown in FIG9 , with the difference being that the second detection device 1122 includes a second negative differential-mode current detection unit 1122c and a second common-mode current detection unit 1122b. Exemplarily, the second negative differential-mode current detection unit 1122c is connected to the negative output terminal n10 of the module assembly 1121 and the second controller 1123, respectively. The second negative differential-mode current detection unit 1122c can detect the negative differential-mode current at the negative output terminal n10 of the module assembly 1121 and transmit it to the second controller 1123. In this way, second controller 1123 can determine the frequency domain component of the received negative differential-mode current, as well as the frequency domain component of the common-mode current. When the frequency domain component of the negative differential-mode current is greater than a second preset amplitude, or when the frequency domain component of the common-mode current is greater than a first preset amplitude, second controller 1123 can control module assembly 1121 to not output electrical energy, thereby achieving arc extinguishing or protective action. Furthermore, not only can negative differential-mode current be detected, but common-mode current can also be detected, enabling detection of multiple currents. This allows for determining whether arcing is occurring from multiple angles, improving the accuracy and effectiveness of arcing detection, reducing detection errors, and enabling timely arc extinguishing measures when arcing occurs, thereby improving the safety of battery cluster use.

[0115] It should be understood that in this embodiment, the implementation of other structures in the energy storage system except the second negative differential-mode current measuring unit 1122c is the same as the specific implementation of the corresponding structure described in the eighth embodiment shown in FIG9 above. For details, please refer to the relevant introduction of the eighth embodiment shown in FIG9 above, and the repeated parts will not be repeated.

[0116] Figure 12 is an exemplary structural diagram of the energy storage system provided in the present application. Referring to Figure 12, the structure of the energy storage system in this embodiment is basically similar to the structure of the energy storage system introduced in the eighth embodiment shown in Figure 9 above, with the difference being that the second detection device 1122 includes: a second positive differential mode current detection unit 1122a, a second negative differential mode current detection unit 1122c, and a second common mode current detection unit 1122b. At this time, the second controller 1123 can determine the frequency domain component of the received positive differential mode current, determine the frequency domain component of the received negative differential mode current, and also determine the frequency domain component in the common mode current. When the frequency domain component of the positive differential mode current is greater than the second preset amplitude, the frequency domain component of the negative differential mode current is greater than the second preset amplitude, or the frequency domain component of the common mode current is greater than the first preset amplitude, the second controller 1123 can control the module combination 1121 not to output electrical energy to the outside, thereby achieving arc extinguishing or protection action. In this way, not only the positive differential mode current and the negative differential mode current can be detected, but also the common mode current can be detected, and the detection of multiple currents can be realized. Then, it can be judged from multiple angles whether arcing occurs, thereby improving the accuracy and effectiveness of arcing detection, reducing detection errors, and taking arc extinguishing measures in time when arcing occurs, thereby improving the safety of battery cluster use.

[0117] That is, this embodiment can be regarded as a combination of the energy storage system introduced in the ninth embodiment shown in FIG. 10 and the energy storage system introduced in the tenth embodiment shown in FIG. 11 , wherein the implementation of the second common-mode current detection unit 1122b can refer to the relevant introduction in the eighth embodiment shown in FIG. 9 , the implementation of the second positive differential-mode current detection unit 1122a can refer to the relevant introduction in the ninth embodiment shown in FIG. 10 , and the implementation of the second negative differential-mode current detection unit 1122c can refer to the relevant introduction in the tenth embodiment shown in FIG. 11 , and the repeated parts will not be repeated.

[0118] It should be understood that the energy storage system in this embodiment is similar to the specific implementation of the corresponding structure introduced in the eighth embodiment shown in Figure 9 above. For details, please refer to the relevant introduction in the eighth embodiment shown in Figure 9 above, and the repeated parts will not be repeated.

[0119] It should be understood that the energy storage system described in any of the embodiments shown in Figures 2 to 8 can be combined with the energy storage system described in any of the embodiments shown in Figures 9 to 12. That is, when the first detection device 142 is provided outside the battery cluster 112, the second detection device 1122 can also be provided inside the battery cluster 112. The presence of both the first detection device 142 and the second detection device 1122 allows for determining whether an arcing phenomenon occurs from more angles, thereby more effectively implementing arcing detection. Furthermore, the first switch k1 and the second switch k2 are provided outside the battery cluster 112, and the third switch k3 and the fourth switch k4 are provided inside the battery cluster 112. This allows for more effective disconnection of the battery cluster 112 from the power supply path, further improving the safety of the battery cluster 112. Furthermore, the first controller 141 and the second controller 1123 can be the same controller, which can reduce the number of controllers to be set, thereby reducing the production cost of the energy storage system; or the first controller 141 and the second controller 1123 can be two different controllers, so that the first detection device 142 and the second detection device 1122 can be controlled separately, avoiding the situation where one of the controllers has an abnormality and the other controller can still prevent the battery cluster 112 from outputting electrical energy to the outside when arcing occurs, thereby effectively suppressing arcing.

[0120] Obviously, those skilled in the art may make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the present application also intends to include such modifications and variations.

Claims

1. An energy storage system, characterized in that: include: Battery cluster, common mode current sensing unit and controller; The battery cluster includes at least two battery modules, and the at least two battery modules are connected in series; One end of the common mode current detection unit is connected to the positive output end of the battery cluster, and the other end of the common mode current detection unit is connected to the negative output end of the battery cluster, and the common mode current detection unit is used to detect the common mode current in the connected circuit; The controller is used to control the path between the output end of the battery cluster and the output end of the energy storage system to be disconnected when the frequency domain component of the common mode current is greater than a first preset amplitude.

2. The energy storage system according to claim 1, characterized in that: The energy storage system further includes a differential mode current detection unit, the differential mode current detection unit is connected to the positive output terminal or the negative output terminal of the battery cluster, and the differential mode current detection unit is used to detect the differential mode current in the connected circuit; The controller is further used to control the path between the output end of the battery cluster and the output end of the energy storage system to be disconnected when the frequency domain component of the differential mode current is greater than a second preset amplitude.

3. The energy storage system according to claim 2, characterized in that: The energy storage system further comprises a DCDC conversion circuit, wherein a positive input terminal of the DCDC conversion circuit is connected to a positive output terminal of the battery cluster, and a negative input terminal of the DCDC conversion circuit is connected to a negative output terminal of the battery cluster; The differential mode current detection unit includes a positive differential mode current detection unit or a negative differential mode current detection unit; The positive differential mode current detection unit is connected to the positive input terminal of the DCDC conversion circuit, or the positive differential mode current detection unit is connected to the positive output terminal of the DCDC conversion circuit; The negative differential mode current detection unit is connected to the negative input terminal of the DCDC conversion circuit, or the negative differential mode current detection unit is connected to the negative output terminal of the DCDC conversion circuit.

4. The energy storage system according to claim 3, characterized in that: The positive differential mode current detection unit or the negative differential mode current detection unit is: any one of a shunt and a current transformer.

5. The energy storage system according to any one of claims 1 to 4, characterized in that: The energy storage system further comprises a DCDC conversion circuit, wherein a positive input terminal of the DCDC conversion circuit is connected to a positive output terminal of the battery cluster, and a negative input terminal of the DCDC conversion circuit is connected to a negative output terminal of the battery cluster; One end of the common-mode current detection unit is connected to the positive input end of the DCDC conversion circuit, and the other end of the common-mode current detection unit is connected to the negative input end of the DCDC conversion circuit; or, one end of the common-mode current detection unit is connected to the positive output end of the DCDC conversion circuit, and the other end of the common-mode current detection unit is connected to the negative output end of the DCDC conversion circuit.

6. The energy storage system according to any one of claims 1 to 5, characterized in that: The energy storage system further includes: a first switch, a second switch and a DCAC conversion circuit, wherein the positive input terminal of the DCAC conversion circuit is connected to the positive output terminal of the battery cluster, and the negative input terminal of the DCAC conversion circuit is connected to the negative output terminal of the battery cluster; One end of the first switch is connected to the positive output end of the battery cluster, and the other end of the first switch is connected to the positive input end of the DCAC conversion circuit; One end of the second switch is connected to the negative output end of the battery cluster, and the other end of the second switch is connected to the negative input end of the DCAC conversion circuit; The controller is used to control the first switch and the second switch to be disconnected when the frequency domain component of the common mode current is greater than a first preset amplitude.

7. The energy storage system according to claim 6, characterized in that: The energy storage system further comprises a DCDC conversion circuit, wherein a positive input terminal of the DCDC conversion circuit is connected to a positive output terminal of the battery cluster, a negative input terminal of the DCDC conversion circuit is connected to a negative output terminal of the battery cluster, a positive output terminal of the DCDC conversion circuit is connected to a positive input terminal of the DCAC conversion circuit, and a negative output terminal of the DCDC conversion circuit is connected to a negative input terminal of the DCAC conversion circuit; One end of the first switch is connected to the positive output end of the battery cluster, and the other end of the first switch is connected to the positive input end of the DCDC conversion circuit; Alternatively, one end of the first switch is connected to the positive output end of the DCDC conversion circuit, and the other end of the first switch is connected to the positive input end of the DCAC conversion circuit.

8. The energy storage system according to claim 6 or 7, characterized in that: The energy storage system further comprises a DCDC conversion circuit, wherein a positive input terminal of the DCDC conversion circuit is connected to a positive output terminal of the battery cluster, a negative input terminal of the DCDC conversion circuit is connected to a negative output terminal of the battery cluster, a positive output terminal of the DCDC conversion circuit is connected to a positive input terminal of the DCAC conversion circuit, and a negative output terminal of the DCDC conversion circuit is connected to a negative input terminal of the DCAC conversion circuit; One end of the second switch is connected to the negative output end of the battery cluster, and the other end of the first switch is connected to the negative input end of the DCDC conversion circuit; or, one end of the second switch is connected to the negative output end of the DCDC conversion circuit, and the other end of the second switch is connected to the negative input end of the DCAC conversion circuit.

9. The energy storage system according to any one of claims 6 to 8, characterized in that: The first switch or the second switch is at least one of a relay, a contactor, and a circuit breaker.

10. The energy storage system according to any one of claims 1 to 9, characterized in that: The common mode current detection unit is a residual current protector, a current transformer or a Hall sensor.

11. A battery cluster, characterized in that: include: One or more battery modules, a common mode current detection unit and a controller, wherein the one or more battery modules are connected in series; One end of the common mode current detection unit is connected to the positive output end of the one or more battery modules, and the other end of the common mode current detection unit is connected to the negative output end of the one or more battery modules; The common mode current detection unit is used to detect the common mode current in the connected circuit; The controller is used to control the battery cluster not to output electric energy externally when the frequency domain component of the common mode current is greater than a first preset amplitude.

12. The battery cluster according to claim 11, characterized in that: The battery cluster further comprises a differential mode current detection unit, the differential mode current detection unit is connected to the positive output terminal or the negative output terminal of the one or more battery modules, and the differential mode current detection unit is used to detect the differential mode current in the connected circuit; The controller is further configured to: when the frequency domain component of the differential mode current is greater than a second preset amplitude, control the battery cluster not to output electric energy externally.

13. The battery cluster according to claim 11 or 12, characterized in that: The battery cluster further includes: a first switch and a second switch; One end of the first switch is connected to the positive output end of the one or more battery modules, and the other end of the first switch is connected to the positive output end of the battery cluster; One end of the second switch is connected to the negative output end of the one or more battery modules, and the other end of the second switch is connected to the negative output end of the battery cluster; The controller is used to control the first switch and the second switch to be disconnected when the frequency domain component of the common mode current is greater than a first preset amplitude.

14. An energy storage system, characterized in that: include: The battery cluster and power conversion circuit according to any one of claims 11 to 13, wherein the power conversion circuit is electrically connected to the battery cluster; The power conversion circuit is used to convert the direct current provided by the battery cluster into alternating current and output it, or to convert the input alternating current into direct current and output it to the battery cluster.

15. A light storage device, characterized in that: include: A photovoltaic power generation device, an inverter, and an energy storage system according to any one of claims 1 to 10 and 14, wherein the inverter is connected to the photovoltaic power generation device and the energy storage system respectively; The photovoltaic power generation device is used to generate direct current; The inverter is used to convert the direct current generated by the photovoltaic power generation device into alternating current and then transmit it to the energy storage system.

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