Over-current protection circuit of energy storage system

Abstract

The utility model provides an over-current protection circuit of an energy storage system, which belongs to the technical field of energy storage and comprises an energy storage module connected between an anode and a cathode of a direct-current high-voltage loop and used for storing electric energy of the direct-current high-voltage loop; the grading over-current protection module is connected with the energy storage module in series, a relay and a first fuse are arranged in the grading over-current protection module, and the relay is used for disconnecting the energy storage module and the direct-current high-voltage loop when the fault current of the energy storage module is smaller than or equal to a preset fault current threshold value; and the first fuse is fused when the fault current of the energy storage module is greater than the preset fault current threshold. The over-current protection circuit can perform over-current multi-stage protection on the energy storage system, is fast in over-current fault response speed of the energy storage system, does not have signal delay, and can quickly realize over-current fault protection of the energy storage system.

Description

Technical Field

[0001] The utility model relates to the technical field of energy storage, and particularly relates to an overcurrent protection circuit for an energy storage system. Background Art

[0002] The overcurrent phenomenon in an energy storage system is a fault state in a power system, which may be caused by various reasons and cause serious consequences to the system. Reasonably setting overcurrent protection measures is crucial for the safe operation of the energy storage system.

[0003] In the prior art, overcurrent protection is set through a battery management system. By monitoring parameters such as the working current and voltage of the energy storage system, an overcurrent threshold is set. When the working current of the energy storage system exceeds this threshold, a cut-off instruction is issued through the battery management system to perform current cut-off protection on the energy storage system. However, the issuance of the instruction may have communication delays or communication failures, resulting in damage to the energy storage system and posing risks.

[0004] It can be seen that in the overcurrent protection of the energy storage system in the prior art, there are technical problems that the overcurrent protection of the energy storage system is not timely due to communication delays or failures, and the energy storage system is damaged. Summary of the Utility Model

[0005] In view of this, it is necessary to provide an overcurrent protection circuit for an energy storage system to solve the technical problems existing in the prior art that in the overcurrent protection of the energy storage system, the overcurrent protection of the energy storage system is not timely due to communication delays or failures, and the energy storage system is damaged.

[0006] To solve the above technical problems, the utility model provides an overcurrent protection circuit for an energy storage system, including:

[0007] An energy storage module connected between the positive and negative poles of a DC high-voltage circuit, and the energy storage module is used to store the electric energy of the DC high-voltage circuit;

[0008] A hierarchical overcurrent protection module connected in series with the energy storage module. A relay and a first fuse are arranged in the hierarchical overcurrent protection module. The relay is used to disconnect the connection between the energy storage module and the DC high-voltage circuit when the fault current of the energy storage module is less than or equal to a preset fault current threshold; the first fuse melts when the fault current of the energy storage module is greater than the preset fault current threshold.

[0009] In a possible implementation manner, a plurality of the energy storage modules are connected in parallel in the DC high-voltage circuit, and each of the energy storage modules is respectively connected in series with the hierarchical overcurrent protection module.

[0010] In a possible implementation manner, the energy storage module includes:

[0011] Multiple battery boxes connected in series for energy storage, with a second fuse provided in each of the battery boxes, wherein the fusing time of the second fuse is greater than that of the first fuse.

[0012] In a possible implementation manner, one end of the hierarchical overcurrent protection module is respectively connected to the positive electrode of the DC high-voltage circuit through a relay K1 and a first fuse R1, and the other end of the hierarchical overcurrent protection module is connected to the negative electrode of the DC high-voltage circuit through a relay K2 and a first fuse R2.

[0013] In a possible implementation manner, the overcurrent protection circuit further includes:

[0014] A load switch, and the DC high-voltage circuit is connected to an AC power supply through the load switch.

[0015] In a possible implementation manner, the overcurrent protection circuit further includes:

[0016] An AC-DC conversion module, the DC end of the AC-DC conversion module is connected to the DC high-voltage circuit, and the AC end of the AC-DC conversion module is connected to the AC power supply.

[0017] In a possible implementation manner, the preset fault current threshold is 2800 A.

[0018] In a possible implementation manner, the fusing time of the second fuse is 0.18 seconds, and the fusing time of the first fuse is 0.018 seconds.

[0019] The beneficial effects of the present utility model are as follows: The overcurrent protection circuit of the energy storage system provided by the present utility model, through the relay and the first fuse of the hierarchical overcurrent protection module, when the fault current of the energy storage module is less than or equal to the preset fault current threshold, the relay is used to disconnect the connection between the energy storage module and the DC high-voltage circuit, and when the fault current of the energy storage module is greater than the preset fault current threshold, the first fuse is used to disconnect the connection between the energy storage module and the DC high-voltage circuit, realizing multi-level protection for the overcurrent fault of the energy storage system, having a fast response speed to the overcurrent fault of the energy storage system, no signal delay, and being able to quickly implement the overcurrent fault protection of the energy storage system. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present utility model. For those skilled in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0021] Figure 1Schematic diagram of an overcurrent protection circuit module for an energy storage system provided by an embodiment of the present invention;

[0022] Figure 2 Overcurrent protection circuit diagram provided by an embodiment of the present invention. Detailed implementation manners

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0024] Referring to "embodiments" herein means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0025] The present invention provides an overcurrent protection circuit for an energy storage system. Combining Figure 1 and Figure 2 , the overcurrent protection circuit of the energy storage system includes an energy storage module 101 connected between the positive and negative poles of a DC high-voltage circuit, and a hierarchical overcurrent protection module 102 connected in series with the energy storage module. Among them, the energy storage module is used to store the electric energy of the DC high-voltage circuit; a relay 103 and a first fuse 104 are provided in the hierarchical overcurrent protection module. The relay 103 is used to disconnect the connection between the energy storage module 101 and the DC high-voltage circuit when the fault current of the energy storage module 101 is less than or equal to a preset fault current threshold; the first fuse 104 melts when the fault current of the energy storage module 101 is greater than the preset fault current threshold.

[0026] In a possible implementation manner, a plurality of the energy storage modules 101 are connected in parallel in the DC high-voltage circuit, and each of the energy storage modules 101 is respectively connected in series with the hierarchical overcurrent protection module 102.

[0027] In a possible implementation manner, the energy storage module 101 includes a plurality of battery boxes 105 connected in series for energy storage, and a second fuse 106 is provided in each of the battery boxes 105. Among them, the melting time of the second fuse 106 is greater than the melting time of the first fuse 104.

[0028] In a possible implementation, two sets of relays 103 and a first fuse 104 are provided in the hierarchical overcurrent protection module 102. One end of the hierarchical overcurrent protection module 102 is connected to the positive pole of the DC high-voltage circuit through the relay K1 and the first fuse R1, and the other end of the hierarchical overcurrent protection module 102 is connected to the negative pole of the DC high-voltage circuit through the relay K2 and the first fuse R2.

[0029] In a possible implementation, the overcurrent protection circuit of the energy storage system further includes a load switch 107, and the DC high-voltage circuit is connected to an AC power supply through the load switch 107.

[0030] In a possible implementation, the overcurrent protection circuit of the energy storage system further includes an AC-DC conversion module 108. The DC end of the AC-DC conversion module 108 is connected to the DC high-voltage circuit, and the AC end of the AC-DC conversion module 108 is connected to the AC power supply.

[0031] In a possible implementation, the preset fault current threshold is 2800 A, the fusing time of the second fuse is 0.18 seconds, and the fusing time of the first fuse is 0.018 seconds.

[0032] The working principle of this practical information is as follows: The AC power supply provides alternating current, which can be an AC generator or directly connected to the mains power. It is connected to the energy storage module through a load switch and an AC-DC conversion module. The AC-DC conversion module is used to convert the alternating current provided by the AC power supply into high-voltage direct current, facilitating energy storage in the energy storage module. The load switch is manually opened or closed to control whether the energy storage system charges. When an overcurrent fault occurs in a certain energy storage module, different protection strategies are adopted based on the magnitude of the fault current. When the fault current is less than or equal to 2800A, overcurrent protection is performed on the energy storage system through a relay, that is, the relay of the hierarchical overcurrent protection module corresponding to this energy storage module is disconnected, disconnecting this energy storage module from the DC high-voltage circuit to achieve the overcurrent protection function. Further, when a short-circuit fault occurs, since the fault current increases instantaneously, when the instantaneously increased fault current is greater than 2800A, in order to ensure the rapid response of the overcurrent protection function, the first fuse in the hierarchical overcurrent protection module corresponding to this energy storage module will fuse within 0.018 seconds, serving the purpose of rapid overcurrent protection. Further, both ends of the hierarchical overcurrent protection module are connected to the DC high-voltage circuit through relays and the first fuse, which can effectively prevent the problem that due to the connection of the hierarchical overcurrent protection module to only one of the positive and negative poles of the DC high-voltage circuit through the relay and the first fuse, the energy storage module still has a circuit with the DC high-voltage module due to grounding and the overcurrent protection is incomplete. Through two groups of relays and the first fuse, the energy storage module can be effectively disconnected from both the positive and negative poles of the DC high-voltage circuit, ensuring the effectiveness of overcurrent protection. Further, when the hierarchical overcurrent protection module fails for some reason, the second fuse of the energy storage module will disconnect within 0.18 seconds, further ensuring the effectiveness of overcurrent protection.

[0033] The overcurrent protection circuit of the energy storage system provided by the present utility model, through the relay and the first fuse of the hierarchical overcurrent protection module, when the fault current of the energy storage module is less than or equal to the preset fault current threshold, uses the relay to disconnect the connection between the energy storage module and the DC high-voltage circuit, and when the fault current of the energy storage module is greater than the preset fault current threshold, uses the first fuse to disconnect the connection between the energy storage module and the DC high-voltage circuit, realizing multi-level protection of the energy storage system against overcurrent. It has a fast response speed to the overcurrent fault of the energy storage system, no signal delay, and can quickly achieve overcurrent fault protection of the energy storage system.

[0034] The above has introduced the overcurrent protection circuit of the energy storage system provided by the present utility model in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model; at the same time, for those skilled in the art, according to the idea of the present utility model, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present utility model.

Claims

1. An overcurrent protection circuit for an energy storage system, characterized in that: include: An energy storage module connected between the positive and negative electrodes of the DC high-voltage circuit, the energy storage module being used to store electrical energy of the DC high-voltage circuit; A hierarchical overcurrent protection module is connected in series with the energy storage module, wherein a relay and a first fuse are provided in the hierarchical overcurrent protection module, wherein the relay is used to disconnect the energy storage module from the DC high-voltage circuit when the fault current of the energy storage module is less than or equal to a preset fault current threshold; and the first fuse is blown when the fault current of the energy storage module is greater than the preset fault current threshold.

2. The overcurrent protection circuit of the energy storage system according to claim 1, characterized in that: A plurality of the energy storage modules are connected in parallel in the DC high voltage circuit, and each of the energy storage modules is respectively connected in series with the hierarchical overcurrent protection module.

3. The overcurrent protection circuit of the energy storage system according to claim 1, characterized in that: The energy storage module comprises: A plurality of battery boxes connected in series for energy storage, each of which is provided with a second fuse, wherein the fusing time of the second fuse is greater than the fusing time of the first fuse.

4. The overcurrent protection circuit of the energy storage system according to claim 1, characterized in that: One end of the graded overcurrent protection module is connected to the positive pole of the DC high voltage circuit through the relay K1 and the first fuse R1, and the other end of the graded overcurrent protection module is connected to the negative pole of the DC high voltage circuit through the relay K2 and the first fuse R2.

5. The overcurrent protection circuit of the energy storage system according to claim 1, characterized in that: Also includes: A load switch, wherein the DC high voltage circuit is connected to the AC power supply through the load switch.

6. The overcurrent protection circuit of the energy storage system according to claim 5, characterized in that: Also includes: An AC / DC conversion module, wherein the DC end of the AC / DC conversion module is connected to the DC high voltage circuit, and the AC end of the AC / DC conversion module is connected to the AC power supply.

7. The overcurrent protection circuit of the energy storage system according to claim 1, characterized in that: The preset fault current threshold is 2800A.

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