Overcurrent protection circuit and energy storage system

Abstract

According to the overcurrent protection circuit and the energy storage system, each battery unit is equipped with the overcurrent protection circuit comprising a current sensor, an overcurrent detection circuit and a switch element, so that the connection between the battery unit and a main circuit can be quickly cut off when the current of the battery unit is abnormal, and each battery unit is accurately protected; faults caused by overcurrent are effectively prevented, and unstable system operation caused by abnormal current is avoided.

Description

Technical Field

[0001] This utility model belongs to the field of energy storage technology, and in particular relates to an overcurrent protection circuit and an energy storage system. Background Technology

[0002] With the rapid development and application of renewable energy, energy storage systems are playing an increasingly important role in power storage and dispatch. Energy storage systems, by storing electrical energy in battery cells, can provide reliable power support during peak electricity demand periods or when renewable energy supply is insufficient. However, as the capacity and scale of energy storage systems increase, the safety and stability of the battery cells have become one of the key issues in the design of energy storage systems.

[0003] In traditional energy storage systems, overcurrent issues in battery cells often lead to battery damage or safety incidents. For example, during charging or discharging, if the current in a battery cell exceeds its safe operating range, it can cause the internal temperature to overheat, leading to thermal runaway, expansion, or even fire. This not only shortens the battery's lifespan but can also threaten equipment and personnel safety. To prevent battery failure due to overcurrent, overcurrent protection measures are typically introduced into energy storage systems. Traditional overcurrent protection measures mostly rely on simple current fuses or circuit breakers, but these methods often suffer from drawbacks such as slow response times, insufficient protection precision, and inability to monitor current changes in real time. Furthermore, as the number of battery cells increases, a single overcurrent protection design is insufficient to meet the safety requirements of large-scale energy storage systems. Utility Model Content

[0004] In view of this, the present invention provides an overcurrent protection circuit and an energy storage system. By introducing an overcurrent protection circuit consisting of a current sensor, an overcurrent detection circuit and a switching element into each battery cell, the connection between the battery cell and the main circuit can be quickly cut off when the current of a battery cell is abnormal, thereby accurately protecting each battery cell, effectively preventing faults caused by overcurrent, and avoiding system instability caused by abnormal current.

[0005] This utility model embodiment provides an overcurrent protection circuit applied to an energy storage system. The energy storage system includes multiple battery cells, and each battery cell includes an overcurrent protection circuit. The overcurrent protection circuit includes: a current sensor for detecting the charging or discharging current of the battery cell; an overcurrent detection circuit connected to the current sensor for comparing the value of the current signal obtained by the current sensor with a preset overcurrent threshold, and outputting a control signal to a switching element when the value of the current signal exceeds the overcurrent threshold; and a switching element for disconnecting the battery cell from the main circuit according to the control signal.

[0006] In one embodiment, the overcurrent detection circuit includes a differential amplifier, an overcurrent comparator, and a programmable logic controller; the input of the differential amplifier is connected to the output of the current sensor, and the output of the differential amplifier is connected to the positive input of the overcurrent comparator, for converting small changes in the current signal into large changes in the voltage; the negative input of the overcurrent comparator is connected to a reference voltage source, and the output of the overcurrent comparator is connected to the programmable logic controller.

[0007] In one embodiment, the differential amplifier includes an input differential pair, a current source, a negative feedback loop, and a common-mode feedback circuit. The input differential pair includes two matched transistors, with the gates of the transistors connected to the two input terminals of the differential signal, the sources of the transistors connected to the output terminal of the current source, and the drains of the transistors forming a differential output. The input terminal of the current source is connected to a reference voltage source, and the output terminal of the current source is connected to the source of the transistor, for providing bias current to the source of the differential pair. The negative feedback loop is connected to the two input terminals of the differential signal, for introducing a feedback signal from the differential output terminal through a resistor network. The common-mode feedback circuit is used to monitor and adjust the common-mode voltage of the differential amplifier.

[0008] In one embodiment, the common-mode feedback circuit includes a detector and a control circuit; the detector is connected to both ends of the differential output terminal to monitor the common-mode voltage of the differential output terminal; the control circuit is used to compensate for deviations in the common-mode voltage.

[0009] In one embodiment, the overcurrent comparator includes an operational amplifier and a current sensing resistor.

[0010] In one embodiment, the overcurrent comparator includes a TLV9001 or an LM358.

[0011] In one embodiment, the resistance of the current sensing resistor is greater than or equal to 1Ω and less than or equal to 10Ω.

[0012] A second aspect of this application provides an energy storage system including multiple battery cells, each battery cell including the overcurrent protection circuit described in the first aspect above.

[0013] The beneficial effects of the embodiments of this application are as follows: by equipping each battery cell with an overcurrent protection circuit including a current sensor, an overcurrent detection circuit and a switching element, the connection between the battery cell and the main circuit can be quickly cut off when the current of a battery cell is abnormal, thereby accurately protecting each battery cell, effectively preventing faults caused by overcurrent, and avoiding system instability caused by abnormal current. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of an energy storage system provided in an embodiment of the present invention;

[0016] Figure 2 A circuit diagram of an overcurrent protection circuit provided in an embodiment of this utility model;

[0017] Figure 3 A circuit diagram of an overcurrent protection circuit provided in another embodiment of this utility model. Detailed Implementation

[0018] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0020] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0023] In the description of the embodiments of this application, the term "multiple frames" refers to two or more (including two).

[0024] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0025] This utility model embodiment provides an overcurrent protection circuit applied to an energy storage system. Please refer to [link / reference]. Figure 1 As shown, Figure 1 This is a schematic diagram of an energy storage system provided according to an embodiment of the present invention. Figure 1 As can be seen, the energy storage system provided in this application includes multiple battery cells 100, and each battery cell 100 includes an overcurrent protection circuit 110. By configuring an overcurrent protection circuit 110 for each battery cell 100 individually, it can be ensured that each battery cell 100 in the energy storage system can be protected independently, avoiding the impact of individual battery cell 100 failures on the stability and reliability of the entire energy storage system. When multiple battery cells 100 are working simultaneously, the energy storage system can effectively prevent local faults from spreading to the entire energy storage system, ensuring the stable operation of the energy storage system.

[0026] like Figure 2 As shown, the overcurrent protection circuit 110 provided by this utility model includes: a current sensor 111 for detecting the charging or discharging current of the battery cell 100; an overcurrent detection circuit 112 connected to the current sensor 111 for comparing the value of the current signal obtained by the current sensor 111 with a preset overcurrent threshold, and outputting a control signal to the switching element 113 when the value of the current signal exceeds the overcurrent threshold; and the switching element 113 for disconnecting the battery cell 110 from the main circuit according to the control signal.

[0027] In one embodiment, such as Figure 3As shown, the overcurrent detection circuit 112 includes a differential amplifier 1121, an overcurrent comparator 1131, and a programmable logic controller 1141. The input terminal of the differential amplifier 1121 is connected to the output terminal of the current sensor 111, and the output terminal of the differential amplifier 1121 is connected to the positive input terminal of the overcurrent comparator 1131, which is used to convert small changes in the current signal into large changes in the voltage. The negative input terminal of the overcurrent comparator 1131 is connected to the reference voltage source 1151, and the output terminal of the overcurrent comparator 1131 is connected to the programmable logic controller 1141.

[0028] The differential amplifier 1121 can convert minute changes in the current signal into larger changes in the voltage, thereby effectively amplifying the weak changes in the current signal and ensuring that even very subtle overcurrent conditions can be accurately detected. The overcurrent comparator 1131, in conjunction with the differential amplifier, can accurately determine whether the current exceeds a predetermined limit based on a threshold set by the reference voltage source 1151, thus achieving high-precision overcurrent detection.

[0029] In one embodiment, the differential amplifier includes an input differential pair, a current source, a negative feedback loop, and a common-mode feedback circuit. The input differential pair includes two matched transistors, with the gates of the transistors connected to the two input terminals of the differential signal, the sources of the transistors connected to the output terminal of the current source, and the drains of the transistors forming a differential output. The input terminal of the current source is connected to a reference voltage source, and the output terminal of the current source is connected to the source of the transistor, for providing bias current to the source of the input differential pair. The negative feedback loop is connected to the two input terminals of the differential signal, for introducing a feedback signal from the differential output terminal through a resistor network. The common-mode feedback circuit is used to monitor and adjust the common-mode voltage of the differential amplifier.

[0030] The differential amplifier employs a current source, a negative feedback loop, and a common-mode feedback circuit to ensure higher linearity and lower common-mode distortion during operation. The common-mode feedback circuit monitors and adjusts the common-mode voltage in real time, preventing signal distortion caused by common-mode voltage variations and improving system stability. The negative feedback loop effectively reduces amplifier gain drift, thereby enhancing long-term circuit stability.

[0031] In one embodiment, the common-mode feedback circuit includes a detector and a control circuit; the detector is connected to both ends of the differential output terminal to monitor the common-mode voltage of the differential output terminal; the control circuit is used to compensate for deviations in the common-mode voltage.

[0032] The common-mode feedback circuit, through the cooperation of detectors and control circuits, can accurately monitor the common-mode voltage of the differential amplifier and compensate for deviations in the common-mode voltage. This not only improves the signal quality of the differential amplifier but also avoids overcurrent detection errors caused by common-mode voltage instability, thereby improving the detection accuracy and reliability of the overall circuit.

[0033] In one embodiment, the overcurrent comparator includes an operational amplifier and a current sensing resistor.

[0034] In one embodiment, the overcurrent comparator includes a TLV9001 or an LM358.

[0035] In one embodiment, the resistance of the current sensing resistor is greater than or equal to 1Ω and less than or equal to 10Ω.

[0036] This utility model also provides an energy storage system, including multiple battery cells, each of which includes the overcurrent protection circuit described in the first aspect above.

[0037] The beneficial effects of the embodiments of this application are as follows: by equipping each battery cell with an overcurrent protection circuit including a current sensor, an overcurrent detection circuit and a switching element, the connection between the battery cell and the main circuit can be quickly cut off when the current of a battery cell is abnormal, thereby accurately protecting each battery cell, effectively preventing faults caused by overcurrent, and avoiding system instability caused by abnormal current.

[0038] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0039] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0040] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An overcurrent protection circuit, characterized by comprising: The application is applied to an energy storage system, which comprises a plurality of battery units, each of which comprises the overcurrent protection circuit, the overcurrent protection circuit comprising: a current sensor for detecting the charging or discharging current of the battery unit; an overcurrent detection circuit connected with the current sensor, for comparing the value of the current signal obtained by the current sensor with a preset overcurrent threshold, and outputting a control signal to a switching element when the value of the current signal exceeds the overcurrent threshold; a switching element for cutting off the connection between the battery unit and the main circuit according to the control signal; wherein the overcurrent detection circuit comprises a differential amplifier, an overcurrent comparator and a programmable logic controller; the input end of the differential amplifier is connected with the output end of the current sensor, the output end of the differential amplifier is connected with the first input end of the overcurrent comparator, for converting the slight change of the current signal into a larger voltage change; the second input end of the overcurrent comparator is used for accessing a reference voltage, and the output end of the overcurrent comparator is connected with the programmable logic controller; the differential amplifier comprises an input differential pair, a current source, a negative feedback loop and a common-mode feedback circuit; the common-mode feedback circuit is used for monitoring and adjusting the common-mode voltage of the differential amplifier, and comprises a detector and a control circuit; the detector is connected to the differential output end of the differential amplifier, for monitoring the common-mode voltage of the differential output end; and the control circuit is used for compensating the deviation of the common-mode voltage.

2. The overcurrent protection circuit of claim 1, wherein, The input differential pair comprises two matched transistors, the gates of the transistors are respectively connected to two input ends of the differential signal, the sources of the transistors are connected to the output end of the current source, and the drains of the transistors form a differential output end.

3. The overcurrent protection circuit of claim 2, wherein, The input end of the current source is connected to a reference voltage source, and the output end of the current source is connected to the source of the transistor, for providing a bias current for the source of the input differential pair.

4. The overcurrent protection circuit of claim 2, wherein, The negative feedback loop is connected to two input ends of the differential signal, for introducing a feedback signal from the differential output end through a resistance network.

5. The overcurrent protection circuit of claim 1, wherein, The overcurrent comparator comprises an operational amplifier and a current sensing resistor.

6. The overcurrent protection circuit of claim 5, wherein, The overcurrent comparator comprises TLV9001 or LM358.

7. The overcurrent protection circuit of claim 5, wherein, The resistance value of the current sensing resistor is between 1Ω and 10Ω.

8. An energy storage system characterized by, The application further provides an energy storage system comprising a plurality of battery units, each of which comprises the overcurrent protection circuit according to any one of claims 1 to 7.

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