Energy storage system

Abstract

The utility model provides an energy storage system, comprising a plurality of battery clusters, each of which is provided with a battery pack and a high-voltage box; a first confluence busbar and a second confluence busbar, the first confluence busbar and the second confluence busbar are respectively connected with a plurality of battery clusters in parallel, the battery clusters are connected with the first confluence busbar and the second confluence busbar through a high-voltage box, and the high-voltage box can alternatively control the connection state of the battery clusters and the first confluence busbar and the connection state of the battery clusters and the second confluence busbar; the input end of the DC-DC converter is connected with the first confluence busbar, and the output end of the DC-DC converter is connected with the second confluence busbar; the DC-DC converter provided by the utility model has the advantages that the efficiency is higher, the voltage between the battery clusters can be quickly balanced, and the battery clusters with large voltage difference can also be effectively balanced. While the voltage between the battery clusters is balanced, the use number of the DC-DC converters is reduced, and the total cost is reduced.

Description

Technical Field

[0001] The utility model relates to the field of energy storage devices, and particularly relates to an energy storage system. Background Art

[0002] There are mainly two ways to parallel battery clusters in existing energy storage systems. One is a centralized energy storage system, and the other is a decentralized energy storage system. In the centralized energy storage system, multiple battery clusters are directly paralleled on the busbar and concentrated into one path for external output by a busbar trunking box. It has a three-level architecture topology, with a simple and mature structure. In the decentralized energy storage system, multiple battery clusters are regulated by DC-DC converters and then paralleled on the busbar, and are concentrated into one path for external output by a busbar trunking box. Compared with the centralized system, each cluster in this scheme adds a DC-DC converter, and the system can adjust the output power of each battery cluster according to the voltage and SOC (State of Charge), and can effectively balance.

[0003] Currently, in the centralized energy storage system, due to the inconsistency of battery cells when multiple battery clusters are directly paralleled, there will be a voltage difference, and the voltage difference will cause current to flow from the high-voltage cluster to the low-voltage cluster. The circulating current causes large capacity loss to the battery system and is prone to cause line overload of the high-voltage battery cluster. And in the centralized energy storage system, a circulating current pre-charge resistor with a resistance value of 5Ω and a power of 200W is generally set in the high-voltage box of the battery cluster to consume the energy between the high and low battery clusters during parallel connection. However, most current power energy storage battery clusters are 300-400KWh energy storage, and the balancing ability of the 200W circulating current pre-charge resistor is very weak, especially for battery clusters with large voltage differences and large SOC differences, it is basically impossible to balance. For the decentralized energy storage system, the cost increases significantly. The battery clusters are charged and discharged through DC-DC converters, and the conversion efficiency will cause the system energy loss of 1-2%. Summary of the Utility Model

[0004] The purpose of the utility model is to provide an energy storage system, which realizes the voltage balance between battery clusters without reducing the system efficiency.

[0005] To achieve the above purpose, the utility model provides the following technical scheme: An energy storage system, comprising: multiple battery clusters, each of which has a battery pack and a high-voltage box; a first busbar and a second busbar, multiple of the battery clusters are respectively paralleled to the first busbar and the second busbar, and the battery clusters are connected to the first busbar and the second busbar through the high-voltage box, and the high-voltage box can alternatively control the connection state of the battery clusters to the first busbar and the second busbar; a DC-DC converter, the input end of the DC-DC converter is connected to the first busbar, and the output end of the DC-DC converter is connected to the second busbar; a busbar trunking box, the busbar trunking box is connected to the second busbar.

[0006] Further, the high-voltage box includes: an active balancing circuit switch mechanism and a main circuit switch mechanism. The battery cluster is connected to the first busbar through the active balancing circuit switch mechanism, and the battery cluster is connected to the second busbar through the main circuit switch mechanism. The active balancing circuit switch mechanism can control the connection state between the battery cluster and the first busbar, and the main circuit switch mechanism can control the connection state between the battery cluster and the second busbar.

[0007] Further, the active balancing circuit switch mechanism includes: a first positive switch and a first negative switch. The first positive switch is connected to the positive electrode of the battery pack of the battery cluster, and the first negative switch is connected to the negative electrode of the battery pack of the battery cluster.

[0008] Further, the DC-DC converter includes: an input control circuit, a power module, and an output control circuit; the first busbar, the input control circuit, the power module, the output control circuit, and the second busbar are sequentially connected. The input control circuit can control the connection state between the power module and the first busbar, the output control circuit can control the connection state between the power module and the second busbar, and the power module can change the output voltage of the first busbar.

[0009] Further, the input control circuit includes a first pre-charge circuit and a main input control circuit connected in parallel. The first pre-charge circuit is connected to the positive electrode of the first busbar and the power module; the main input control circuit is connected to the positive electrode of the first busbar and the power module.

[0010] Further, the output control circuit includes a second pre-charge circuit and a main output control circuit connected in parallel. The second pre-charge circuit is connected to the positive electrode of the second busbar and the power module; the main output control circuit is connected to the positive electrode of the second busbar and the power module.

[0011] Further, the power module is a bidirectional buck-boost circuit; and / or a circuit breaker is provided between the output control circuit and the second busbar.

[0012] Further, the busbar box includes: a busbar switch and a surge protection mechanism. The input end of the busbar box is connected to the output end of the busbar box through the busbar switch, and the surge protection mechanism is connected to the busbar switch.

[0013] Further, the cross-sectional area of the first busbar is smaller than that of the second busbar; and / or a circuit breaker is provided between the high-voltage box and the second busbar.

[0014] Further, the energy storage system further includes: a battery management system BMS, which is connected to the battery pack, the active equalization circuit switching mechanism, and the main circuit switching mechanism. The BMS can detect the voltage of the battery pack and control the working states of the active equalization circuit switching mechanism and the main circuit switching mechanism according to the detected voltage of the battery pack.

[0015] Analysis shows that the present utility model discloses an energy storage system. The DC-DC converter of the present utility model has higher efficiency and can quickly equalize the voltage between battery clusters. It can also effectively equalize the battery clusters with large voltage differences. During normal discharge, the battery clusters can be directly connected in parallel and converged to the busbar without passing through the DC-DC converter, which will not cause a decrease in system efficiency. At the same time, while equalizing the voltage between battery clusters, the number of DC-DC converters used is reduced, and the overall cost is lowered. Description of the Drawings

[0016] The schematic diagrams in the specification that form a part of this application are used to provide a further understanding of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation to the present utility model. Among them:

[0017] Figure 1 The circuit diagram of an embodiment of the present utility model.

[0018] Figure 2 The circuit diagram of the equalization state of an embodiment of the present utility model.

[0019] Figure 3 The structural schematic diagram of an embodiment of the present utility model.

[0020] Description of the reference numerals: 1. Battery pack; 2. High-voltage box; 3. First busbar; 4. Second busbar; 5. DC-DC converter; 6. Busbar box; 7. Surge protector. Detailed Embodiments

[0021] The present utility model will be described in detail below with reference to the drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present utility model rather than a limitation of the present utility model. In fact, those skilled in the art will clearly understand that modifications and variations can be made to the present utility model without departing from the scope or spirit of the present utility model. For example, the features shown or described as part of one embodiment can be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present utility model includes such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0022] In the description of the present utility model, the orientation or positional relationship indicated by terms such as "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model rather than requiring the present utility model to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. The terms "connected", "joined", and "arranged" used in the present utility model should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component; it can be a wired connection, a radio connection, or a wireless communication signal connection. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0023] One or more examples of the present utility model are shown in the accompanying drawings. The detailed description uses numerical and alphabetical labels to refer to features in the drawings. Similar or like labels in the drawings and the description have been used to refer to similar or like parts of the present utility model. As used herein, terms such as "first", "second", "third", and "fourth" are used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of individual components.

[0024] As Figure 1As shown in the figure, according to an embodiment of the present utility model, an energy storage system is provided, including: a plurality of battery clusters, a first busbar 3 and a second busbar 4, and a DC-DC converter 5 and a busbar box 6. Among them, the battery cluster has a battery pack 1 and a high-voltage box 2 connected in series with the battery pack 1. One high-voltage box 2 is configured for each battery cluster, and the battery cluster is connected to the first busbar 3 and the second busbar 4 through the high-voltage box 2, and the high-voltage box 2 can alternatively control the connection state between the battery cluster and the first busbar 3 and the second busbar 4. That is, when the battery cluster is connected to the busbar under the control of the high-voltage box 2, the battery cluster is either connected to the first busbar 3, and at this time the battery cluster is disconnected from the second busbar 4; or connected to the second busbar 4, and at this time the battery cluster is disconnected from the first busbar 3. The first busbar 3 serves as the input of the active equalization circuit and is used to connect the battery clusters involved in the equalization between the battery clusters. When equalizing, the battery cluster with the highest voltage is connected. The second busbar 4 combines a plurality of battery clusters into one path and then connects to the busbar box 6. A plurality of battery clusters are connected in parallel to the first busbar 3 and also in parallel to the second busbar 4. The DC-DC converter 5 can change the voltage input to the DC-DC converter 5 and then output the changed voltage. The input end of the DC-DC converter 5 is connected to the first busbar 3, and the output end of the DC-DC converter 5 is connected to the second busbar 4. The busbar box 6 (or called busbar cabinet) is connected to the second busbar 4. When the energy storage system is in a normal discharge working state, the busbar box 6 is further connected to an external device to achieve output.

[0025] By setting the first busbar 3 and the second busbar 4 connected to the busbar box 6, setting the high-voltage box 2 capable of alternatively controlling the connection state between the battery cluster and the first busbar 3 and the second busbar 4, and setting the DC-DC converter 5 between the first busbar 3 and the second busbar 4, when the high-voltage box 2 controls the connection between the battery cluster and the second busbar 4, the battery cluster, the high-voltage box 2, the second busbar 4 and the busbar box 6 form an electrical circuit loop, and this electrical circuit loop is called the main loop, and this energy storage system is in the normal discharge working state or the normal charge working state; when the high-voltage box 2 controls the connection between the battery cluster and the first busbar 3, the highest-voltage battery cluster, the high-voltage box 2, the first busbar 3, the DC-DC converter 5, the second busbar 4 and the lowest-voltage battery cluster form an electrical circuit loop, and this electrical circuit loop is called the active equalization loop, so that this energy storage system is in the active equalization working state, and this working state is conducive to making the voltage difference between battery clusters (the highest-voltage battery cluster and the lowest-voltage battery cluster) meet the relevant requirements. Therefore, when equalizing between battery clusters, compared with the aforementioned centralized system, the DC-DC converter 5 is used, with higher efficiency, capable of quickly equalizing, and can also effectively equalize battery clusters with a large voltage difference. Compared with the aforementioned decentralized system, during normal discharge, the battery clusters are still directly connected in parallel to the second busbar, avoiding the phenomenon of the energy storage system efficiency decrease caused by passing through the DC-DC converter 5. When realizing voltage equalization between battery clusters, the number of used DC-DC converters 5 is reduced, and the cost is lowered.

[0026] It should be noted that the number and output power of the above-mentioned battery clusters can be selected according to the output requirements. Usually, the number of battery clusters is more than 3. The number of the above-mentioned battery packs 1 can also be selected according to the output requirements. Usually, the number is multiple. When multiple battery packs 1 are connected, they can be connected in series with each other. This embodiment does not limit this. The above-mentioned battery pack 1 has an MSD (Manual Service Disconnect, maintenance switch). Usually, the first busbar 3 is only connected to one battery cluster, and when the first busbar 3 is connected to any battery cluster, the second busbar 4 is also only connected to one battery cluster, so as to realize the input of the electric energy of one battery cluster to another battery cluster.

[0027] The high-voltage box 2 includes: an active equalization loop switch mechanism and a main loop switch mechanism. The battery packs 1 of the battery cluster are connected to the first busbar 3 through the active equalization loop switch mechanism, and the battery packs 1 of the battery cluster are connected to the second busbar 4 through the main loop switch mechanism. The active equalization loop switch mechanism can control the connection state between the battery cluster and the first busbar 3, such as conduction and disconnection; the main loop switch mechanism can control the connection state between the battery cluster and the second busbar 4, such as conduction and disconnection, making the switching control between the active equalization working state and the normal working state simple and convenient.

[0028] The active balancing circuit switch mechanism includes: a first positive switch and a first negative switch. One end of the first positive switch is connected to the positive electrode of battery pack 1 of the battery cluster, and the other end of the first positive switch is connected to the positive electrode of the first busbar 3; the first negative switch is connected to the negative electrode of battery pack 1 of the battery cluster, and the other end of the first negative switch is connected to the negative electrode of the first busbar 3. When the first positive switch and the first negative switch are both closed, the battery cluster is connected to the first busbar 3. The first positive switch can be a contactor KM3, and the first negative switch can be a contactor KM4. In other embodiments, the positive switch and the negative switch can also be a circuit breaker with electric operation in mechanical switches, MOS, IGBT, etc. in semiconductor switches. The specific types of switches are not specifically limited in this embodiment.

[0029] The main circuit switch mechanism includes: a second positive switch and a second negative switch. The second positive switch is connected to the positive electrode of battery pack 1 of the battery cluster, and the second negative switch is connected to the negative electrode of battery pack 1 of the battery cluster. When the second positive switch and the second negative switch are both closed, the battery cluster is connected to the second busbar 4. The second positive switch can be a contactor KM1, and the second negative switch can be a contactor KM2. In other embodiments, the positive switch and the negative switch can also be other types of switches. The above-mentioned first positive contactor KM1, first negative contactor KM2, second positive contactor KM3, and second negative contactor KM4 can all be in an open state before the energy storage system is started.

[0030] Preferably, the positive electrode of battery pack 1 of the battery cluster is respectively connected to the active balancing circuit switch mechanism and the main circuit switch mechanism through a fuse FU1, so as to improve the safety protection performance of this energy storage system.

[0031] The energy storage system further includes: a BMS (Battery Management System), which is connected to battery pack 1 of the battery cluster, the active balancing circuit switch mechanism, and the main circuit switch mechanism. The BMS can detect the voltage of the battery cluster and control the working states of the active balancing circuit switch mechanism and the main circuit switch mechanism according to the detected voltage of the battery cluster, so as to facilitate the energy storage system to be in an active balancing state, a normal charging state, or a normal discharging state.

[0032] As Figure 2 shown, Figure 2The arrow direction in [the figure] represents the current transmission direction. The above-mentioned BMS usually starts when the low-voltage power is applied to the energy storage system. The BMS can detect the voltage of the battery cluster and change the conduction state of the high-voltage box 2 according to the voltage condition of the battery cluster. Usually, when the voltage of the battery cluster is not in an equilibrium state, that is, when the equilibrium condition is met (such as the voltage difference between battery clusters is greater than the first preset voltage difference), the BMS can connect the battery cluster with the highest voltage to the first busbar 3, connect the battery cluster with the lowest voltage to the second busbar 4, and disconnect the remaining battery clusters from the first busbar 3 and the second busbar 4 at the same time. At this time, the battery cluster with the highest voltage can output electrical energy to the DC-DC converter 5 through the first busbar 3, and after the voltage is regulated by the DC-DC converter 5, it is input to the battery cluster with the lowest voltage through the second busbar 4, so as to realize the equalization operation of the battery cluster. Usually, after it is determined that the voltage difference between the two battery clusters undergoing the equalization operation is less than the second preset voltage difference, the equalization operation of the battery cluster is stopped. Preferably, the second preset voltage difference is less than the first preset voltage difference. In practical applications, the above-mentioned first preset voltage difference can be 10V, and the second preset voltage difference can be 5V. This embodiment does not limit the specific values of the first preset voltage difference and the second preset voltage difference, and in other embodiments, they can also be other values.

[0033] The DC-DC converter 5 includes an input control circuit, a power module, and an output control circuit; the first busbar 3, the input control circuit, the power module, the output control circuit, and the second busbar 4 are connected in sequence. The input control circuit can control the connection state between the power module and the first busbar 3, the output control circuit can control the connection state between the power module and the second busbar 4, the power module can change the output voltage of the first busbar 3, and both between the power module and the input control circuit and between the power module and the output control circuit are connected through a DCFILTER (DC filter).

[0034] The input control circuit includes a first pre-charge circuit and a main input control circuit connected in parallel. The first pre-charge circuit is connected to the positive pole of the first busbar 3 and the power module, and the main input control circuit is connected to the positive pole of the first busbar 3 and the power module.

[0035] The output control circuit includes a second pre-charge circuit and a main output control circuit connected in parallel. The second pre-charge circuit is connected to the positive pole of the second busbar 4 and the power module; the main output control circuit is connected to the positive pole of the second busbar 4 and the power module.

[0036] The above-mentioned main input control circuit includes a positive contactor KM5 and a negative contactor KM6. The positive contactor KM5 and the negative contactor KM6 are respectively connected to the positive pole and the negative pole of the first busbar 3.

[0037] The above-mentioned main output control circuit includes a positive contactor KM7 and a negative contactor KM8. The positive contactor KM7 and the negative contactor KM8 are respectively connected to the positive and negative poles of the second busbar 4.

[0038] The above-mentioned positive contactor KM5, negative contactor KM6, positive contactor KM7 and negative contactor KM8 are all in the off state before the energy storage system starts.

[0039] A fuse FU2 is usually also provided between the positive contactor KM5 and the positive pole of the first busbar 3.

[0040] The first precharge circuit includes a precharge contactor K1 and a resistor R1. The precharge contactor K1 and the resistor R1 are connected in series and then connected in parallel with the positive contactor KM5. The second precharge circuit includes a precharge contactor K2 and a resistor R2. The precharge contactor K2 and the resistor R2 are connected in series and then connected in parallel with the positive contactor KM7.

[0041] The power module is a bidirectional buck-boost circuit; and / or a circuit breaker is provided between the output control circuit and the second busbar 4.

[0042] The power module includes a support capacitor C1, a support capacitor C2, an inductor L1, and IGBTs of the upper and lower bridge arms. The entire power module constitutes a bidirectional buck-boost BUCK-BOOST circuit.

[0043] During the equalization operation, the following processing can be performed. Close the negative contactor KM6 and the precharge contactor K1 to precharge the support capacitor C1 of the DC-DC converter 5. After the voltage of the support capacitor C1 reaches 95% of the voltage of the battery cluster with the highest voltage, the precharge ends. Close the main positive contactor KM5 and disconnect the precharge contactor K1 to enter the hot standby state. The DC-DC converter 5 closes the positive contactor KM7 and the negative contactor KM8 at any time upon receiving an instruction and outputs power at any time. Then close the positive contactor KM1 and the negative contactor KM2 of the high-voltage box 2 of the battery cluster with the lowest voltage, and then control the DC-DC converter 5 to output power until the voltage difference between the two battery clusters is less than the set voltage and then stop outputting power.

[0044] As Figure 3 shown, Figure 3 The arrow direction in represents the current transmission direction. The busbar box 6 includes: a busbar switch and an SPD (Surge Protective Device, surge protector 7). The input end of the busbar box 6 is connected to the output end of the busbar box 6 through the busbar switch, and the surge protector 7 is connected to the busbar switch. Fuses FU are provided between the busbar switch and the output end of the busbar box 6 and between the busbar switch and the surge protector 7.

[0045] When the voltage of the battery cluster is in an equilibrium state, that is, when the equilibrium condition is not met (for example, the voltage difference between battery clusters is less than the first preset voltage difference), the BMS can connect the battery cluster to the second busbar, and the battery cluster outputs current to the busbar box through the second busbar, thereby realizing the convergence of the currents of the battery clusters by the busbar box.

[0046] Circuit breakers QL are provided between the main circuit switch mechanism and the second busbar 4, between the main output control circuit and the second busbar 4, and between the high-voltage box 2 and the second busbar 4. The above-mentioned circuit breaker QL can further improve the connection safety between the circuit and the second busbar 4.

[0047] The cross-sectional area of the first busbar 3 is smaller than that of the second busbar 4. Since the second busbar 4 is connected to the power line coming from the main circuit of the high-voltage box 2, and its function is to converge the currents of multiple battery clusters into one path and then connect to external devices, the cross-sectional area needs to be selected according to the maximum current of the energy storage system. The first busbar 3 is the power line coming from the active equalization circuit of the high-voltage box 2, and its function is to connect the equalization circuits of multiple battery clusters to form the input of the equalization circuit. Only the high-voltage box 2 of the battery cluster with the highest voltage will be closed at the same time in the equalization circuit. Therefore, the copper bar can have a smaller cross-sectional area according to the power of the DC-DC converter 5.

[0048] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0049] The DC-DC converter of the present invention has higher efficiency and can quickly equalize the voltages between battery clusters, and can also effectively equalize battery clusters with large voltage differences. During normal discharge, the battery clusters can be directly connected in parallel and converged to the busbar without passing through the DC-DC converter, which will not cause a decrease in system efficiency. At the same time, while equalizing the voltages between battery clusters, the number of DC-DC converters used is reduced, and the overall cost is lowered.

[0050] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An energy storage system, characterized in that, Comprising: Multiple battery clusters, each battery cluster having a battery pack and a high-voltage box; A first busbar and a second busbar, with multiple of the battery clusters connected in parallel to the first busbar and the second busbar respectively. The battery clusters are connected to the first busbar and the second busbar through the high-voltage box, and the high-voltage box can alternatively control the connection state between the battery clusters and the first busbar and the second busbar; A DC-DC converter, the input end of the DC-DC converter being connected to the first busbar, and the output end of the DC-DC converter being connected to the second busbar; A busbar box, the busbar box being connected to the second busbar.

2. The energy storage system according to claim 1, wherein, The high-voltage box includes: an active equalization circuit switch mechanism and a main circuit switch mechanism. The battery cluster is connected to the first busbar through the active equalization circuit switch mechanism, and the battery cluster is connected to the second busbar through the main circuit switch mechanism. The active equalization circuit switch mechanism can control the connection state between the battery cluster and the first busbar, and the main circuit switch mechanism can control the connection state between the battery cluster and the second busbar.

3. The energy storage system according to claim 2, characterized in that The active equalization circuit switch mechanism includes: a first positive switch and a first negative switch. The first positive switch is connected to the positive pole of the battery pack of the battery cluster, and the first negative switch is connected to the negative pole of the battery pack of the battery cluster.

4. A energy storage system according to claim 1, wherein The DC-DC converter includes: an input control circuit, a power module, and an output control circuit; The first busbar, the input control circuit, the power module, the output control circuit, and the second busbar are connected in sequence. The input control circuit can control the connection state between the power module and the first busbar, the output control circuit can control the connection state between the power module and the second busbar, and the power module can change the output voltage of the first busbar.

5. A energy storage system according to claim 4, wherein, The input control circuit includes a first precharge circuit and a main input control circuit connected in parallel. The first precharge circuit is connected to the positive pole of the first busbar and the power module; the main input control circuit is connected to the positive pole of the first busbar and the power module.

6. A energy storage system according to claim 4, wherein The output control circuit includes a second precharge circuit and a main output control circuit connected in parallel. The second precharge circuit is connected to the positive pole of the second busbar and the power module; the main output control circuit is connected to the positive pole of the second busbar and the power module.

7. A energy storage system according to any one of claims 4-6, characterized in that, The power module is a bidirectional buck-boost circuit; and / or A circuit breaker is provided between the output control circuit and the second busbar.

8. An energy storage system according to claim 1, wherein, The busbar box includes: a busbar switch and a surge protection mechanism. The input end of the busbar box is connected to the output end of the busbar box through the busbar switch, and the surge protection mechanism is connected to the busbar switch.

9. A energy storage system according to claim 1, characterized in that, The cross-sectional area of the first busbar is smaller than the cross-sectional area of the second busbar; and / or A circuit breaker is provided between the high-voltage box and the second busbar.

10. A energy storage system according to claim 2, characterized in that, The energy storage system further includes: a battery management system BMS, the BMS is connected to the battery pack, the active equalization circuit switching mechanism and the main circuit switching mechanism, and the BMS can detect the voltage of the battery pack and control the working states of the active equalization circuit switching mechanism and the main circuit switching mechanism according to the detected voltage of the battery pack.

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