Protection circuit of photovoltaic module, junction box and photovoltaic module

Abstract

The utility model relates to a protection circuit of a photovoltaic module, a junction box and the photovoltaic module. The protection circuit comprises a bypass diode and a shunt branch, the bypass diode and the shunt branch are connected in parallel, a first end of the bypass diode connected in parallel with the shunt branch is used for being connected with a first end of a target battery string of a photovoltaic module to be protected, and a second end of the bypass diode connected in parallel with the shunt branch is used for being connected with a second end of the target battery string. The target battery string is one of the plurality of battery strings; and the shunt branch is used for conducting a path between the first end and the second end of the target battery string when the target battery string is in a reverse overvoltage state and the bypass diode is not conducted. The access between the first end and the second end of the target battery string is conducted through the shunt branch, so that the shunt effect is achieved, the target battery string is prevented from being overheated, and the target battery string can be better protected.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a protection circuit, a junction box, and a photovoltaic module of a photovoltaic module. Background Art

[0002] With the development of energy technology, photovoltaic modules that use solar cells to emit light have emerged. During the operation of the photovoltaic module, if a shadow blocks one or some of the solar cells in the photovoltaic module, the blocked solar cell will stop generating electricity and become a high-resistance resistor. A portion of the output of other solar cells connected in series with the blocked solar cell will be consumed by the blocked solar cell, which may cause the blocked solar cell to overheat and be damaged.

[0003] In conventional technology, a bypass diode is installed in parallel next to a solar cell. When a solar cell is blocked, the bypass diode will automatically conduct, short-circuiting the blocked solar cell and diverting the current that would otherwise flow through the blocked solar cell to protect the circuit.

[0004] However, traditional technology may have the problem of poor protection effect. Utility Model Content

[0005] Based on this, it is necessary to provide a photovoltaic module protection circuit, a junction box, and a photovoltaic module that can better protect the photovoltaic module in response to the above technical problems.

[0006] A protection circuit for a photovoltaic module, the photovoltaic module comprising a plurality of battery strings, the plurality of battery strings being connected in series in sequence, the protection circuit comprising: a bypass diode and a shunt branch, the bypass diode and the shunt branch being connected in parallel, wherein:

[0007] The first end of the bypass diode and the shunt branch connected in parallel is used to be connected to the first end of the target battery string of the photovoltaic assembly to be protected, and the second end of the bypass diode and the shunt branch connected in parallel is used to be connected to the second end of the target battery string, and the target battery string is one of the multiple battery strings;

[0008] The shunt branch is used to conduct a path between the first end and the second end of the target battery string when the target battery string is in a reverse overvoltage state and the bypass diode is not conducting.

[0009] In one embodiment, the protection circuit further includes:

[0010] A reverse overvoltage detection component, used to detect a reverse overvoltage feature of the target battery string;

[0011] The processor is connected to the reverse overvoltage detection component, the voltage sensor, and the shunt branch, respectively, and is used to control the shunt branch to close to conduct the path between the first end and the second end of the target battery string when determining that the target battery string has a reverse overvoltage fault according to the reverse overvoltage characteristics of the target battery string and the bypass diode is in a non-conducting state.

[0012] In one of the embodiments, the reverse overvoltage detection component includes: a current sensor, the current sensor is connected to the target battery string and is used to collect the current of the target battery string;

[0013] The processor is connected to the current sensor and is used to determine that a reverse overvoltage fault occurs in the target battery string when the current of the target battery string is less than a current threshold.

[0014] In one of the embodiments, the reverse overvoltage detection component includes: a temperature sensor, the temperature sensor is used to collect the temperature of the target battery string;

[0015] The processor is connected to the temperature sensor, and is further configured to determine that a reverse overvoltage fault occurs in the target battery string when the temperature of the target battery string is greater than a temperature threshold.

[0016] In one of the embodiments, the reverse overvoltage detection component includes: an image sensor, the image sensor being used to capture a surface image of the target battery string;

[0017] The processor is connected to the image sensor, and is further configured to determine whether a reverse overvoltage fault occurs in the target battery string according to the surface image of the target battery string.

[0018] In one embodiment, the protection circuit further includes:

[0019] an alarm component connected to the processor;

[0020] The processor is used for sending an alarm instruction to the alarm component to make the alarm component output an alarm signal when determining that the target battery string is in a reverse overvoltage state.

[0021] In one of the embodiments, the shunt branch includes: a controllable switch, and the controllable switch includes one of a relay, a metal-oxide semiconductor field effect transistor, an insulated gate bipolar transistor, a power transistor, and a gate turn-off thyristor.

[0022] A junction box for a photovoltaic assembly comprises: at least one protection circuit as mentioned above.

[0023] A photovoltaic assembly comprises a plurality of battery strings and the aforementioned protection circuit, wherein the plurality of battery strings are sequentially connected in series.

[0024] In one embodiment, the photovoltaic assembly includes a plurality of battery string groups, the battery string groups include a first battery string and a second battery string, the first battery strings of the plurality of battery string groups are connected in series in sequence, and the second battery strings of the plurality of battery string groups are connected in parallel with the first battery strings;

[0025] The first end of the bypass diode and the shunt branch connected in parallel is connected to the first end of the target battery string group, and the second end of the bypass diode and the shunt branch connected in parallel is connected to the second end of the target battery string group, and the target battery string group is one of the first battery string or the second battery string of the multiple battery string groups;

[0026] The first end of the bypass diode and the shunt branch connected in parallel is connected to the first end of the target battery string group, and the second end of the bypass diode and the shunt branch connected in parallel is connected to the second end of the target battery string group, and the target battery string group is one of the multiple battery string groups;

[0027] The shunt branch is used to conduct a path between the first end and the second end of the target battery string group when the target battery string group is in a reverse overvoltage state and the bypass diode is not conducting.

[0028] The protection circuit, junction box, and photovoltaic assembly of the above-mentioned photovoltaic assembly can automatically conduct when the target battery string is blocked, that is, when the target battery string is in a reverse overvoltage state, by setting a bypass diode, short-circuiting the target battery string, shunting the current that would otherwise flow through the target battery string, protecting the circuit, and maintaining the current value of the circuit output without a significant decrease. By setting a shunt branch in parallel with the bypass diode, the path between the first end and the second end of the target battery string can be turned on when the target battery string is in a reverse overvoltage state and the bypass diode is not turned on, so that when the target battery string is blocked, but the degree of blocking is small, and the voltage difference between the two ends of the target battery string is not enough to turn on the bypass diode, the shunt branch is used to conduct the path between the first end and the second end of the target battery string, thereby achieving the shunting effect, avoiding overheating of the target battery string, and better protecting the target battery string. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] FIG1 is a schematic diagram of the structure of a protection circuit of a photovoltaic module in one embodiment;

[0031] FIG2 is a second schematic diagram of the structure of a protection circuit of a photovoltaic module in one embodiment;

[0032] FIG3 is a third schematic diagram of the structure of a protection circuit of a photovoltaic module in one embodiment;

[0033] FIG4 is a fourth structural schematic diagram of a protection circuit of a photovoltaic module in one embodiment;

[0034] FIG5 is a fifth structural diagram of a protection circuit of a photovoltaic module in one embodiment;

[0035] FIG5a is a sixth structural schematic diagram of a protection circuit of a photovoltaic module in one embodiment;

[0036] FIG6 is a schematic diagram of a junction box structure of a protection circuit of a photovoltaic module in one embodiment;

[0037] FIG7 is a schematic diagram of the structure of a photovoltaic module in one embodiment;

[0038] FIG8 is a second schematic diagram of the structure of a photovoltaic module in one embodiment;

[0039] FIG9 is a schematic diagram of a photovoltaic module in one embodiment;

[0040] FIG. 10 is a schematic diagram of voltage and current of a photovoltaic module in one embodiment.

[0041] Description of reference numerals:

[0042] 10-battery string, D1-bypass diode, 20-shunt branch, 30-reverse overvoltage detection component, 40-processor, 31-current sensor, 32-temperature sensor, 33-image sensor, 50-alarm component, 100-junction box, 200-photovoltaic component, 300-battery string group, 301-first battery string, 302-second battery string. DETAILED DESCRIPTION

[0043] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0045] It can be understood that the terms "first", "second", etc. used in the present application can be used in this article to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element.

[0046] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0047] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element, or connected to the other element through an intermediate element. In addition, the "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if there is transmission of electrical signals or data between the connected objects.

[0048] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0049] In one embodiment, as shown in FIG1 , a protection circuit of a photovoltaic module is provided. The photovoltaic module includes a plurality of battery strings 10, and the plurality of battery strings 10 are sequentially connected in series. The protection circuit includes: a bypass diode D1 and a shunt branch 20, and the bypass diode D1 and the shunt branch 20 are connected in parallel, wherein:

[0050] The first end of the bypass diode D1 and the shunt branch 20 connected in parallel is used to connect to the first end of the target battery string 10 of the photovoltaic component to be protected, and the second end of the bypass diode D1 and the shunt branch 20 connected in parallel is used to connect to the second end of the target battery string 10, which is one of the multiple battery strings 10.

[0051] The bypass diode D1 and the shunt branch 20 are connected in parallel and in parallel with the target battery string 10. When the bypass diode D1 is turned on, the bypass diode D1 short-circuits the target battery string 10, and the current can flow through the bypass diode D1 instead of the target battery string 10. When the shunt branch 20 is turned on, the current can flow through the shunt branch 20 instead of the target battery string 10.

[0052] The shunt branch 20 is provided with a controllable switch S, which may be one of a relay, a metal-oxide semiconductor field effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), a power transistor (GTR), and a gate turn-off thyristor (GTO). The controllable switch S can be actively turned on under external control and is a fully controlled switch, thereby turning on the path between the first end and the second end of the target battery string 10.

[0053] The shunt branch 20 is used to conduct the path between the first end and the second end of the target battery string 10 when the target battery string 10 is in a reverse overvoltage state and the bypass diode D1 is not conducting.

[0054] Among them, the shunt branch 20 also includes a control circuit corresponding to the controllable switch S, which can actively control the controllable switch S to be turned on when it is determined that the target battery string 10 is in a reverse overvoltage state and the bypass diode D1 is not turned on. The control circuit may include a communication module, an analog-to-digital converter, a comparator, an amplifier, a processor, etc., as long as it can receive an external detection signal that determines that the target battery string 10 is in a reverse overvoltage state and the bypass diode D1 is not turned on, and then control the controllable switch S to be turned on.

[0055] The battery string 10 is a solar cell. During the operation of the solar cell, if a shadow blocks one or some solar cells, the output of other batteries connected to the shadowed battery string 10 will be consumed by the battery. This energy consumption will cause local breakdown of the battery PN junction and cause local overheating, which is the hot spot effect. When a battery is blocked, it will stop generating electricity and become a high-resistance resistor. At the same time, other batteries will cause it to be reverse biased, so that it will be in a reverse overvoltage state.

[0056] Among them, the conduction voltage of the bypass diode D1 can be 0.4V in the forward direction. When the target battery string 10 is blocked and is in a reverse overvoltage state, the voltage difference between its two ends will become larger. When it reaches 0.4V, the bypass diode D1 will be turned on, and the current originally flowing through the target battery string 10 will be shunted. However, when the target battery string 10 is blocked to a lesser extent, although it is in a reverse overvoltage state, the voltage difference between its two ends does not reach 0.4V, then the bypass diode D1 will not be turned on. At this time, the target battery string 10 is not bypassed, and it is still connected in series in the circuit as a large resistor, which will cause the current of the circuit to drop, the power to decrease, and it will also heat up seriously. Therefore, it is necessary to control the conduction of the shunt branch 20 to shunt the current originally flowing through the target battery string 10. The protection circuit of the present application solves the problem that the bypass diode D1 does not conduct when the target battery string 10 is only slightly blocked.

[0057] In this embodiment, by setting the bypass diode D1, it can automatically conduct when the target battery string 10 is blocked, that is, when the target battery string 10 is in a reverse overvoltage state, the target battery string 10 is short-circuited, and the current that would otherwise flow through the target battery string 10 is diverted to protect the circuit, while maintaining the current value of the circuit output will not drop significantly. By setting the shunt branch 20 in parallel with the bypass diode D1, the path between the first end and the second end of the target battery string 10 can be turned on when the target battery string 10 is in a reverse overvoltage state and the bypass diode D1 is not turned on, so that when the target battery string 10 is blocked, but the degree of blocking is small, and the voltage difference between the two ends of the target battery string 10 is not enough to turn on the bypass diode D1, the shunt branch 20 is used to conduct the path between the first end and the second end of the target battery string 10, so as to achieve the shunt effect, avoid overheating of the target battery string 10, and better protect the target battery string 10.

[0058] In one embodiment, as shown in FIG2 , the protection circuit further includes: a reverse overvoltage detection component 30 and a processor 40. Wherein:

[0059] The reverse overvoltage detection component 30 is used to detect the reverse overvoltage feature of the target battery string 10 .

[0060] The reverse overvoltage feature of the target battery string 10 may be one of the following: a significant decrease in the current of the target battery string 10 , an abnormal increase in the temperature of the target battery string 10 , or the target battery string 10 being obstructed from the outside.

[0061] The processor 40 is respectively connected to the reverse overvoltage detection component 30, the voltage sensor, and the shunt branch 20, and is used to control the shunt branch 20 to close, so as to conduct the path between the first end and the second end of the target battery string 10, when it is determined that the target battery string 10 has a reverse overvoltage fault according to the reverse overvoltage characteristics of the target battery string 10 and the bypass diode D1 is in a non-conducting state.

[0062] The processor 40 can analyze the reverse overvoltage characteristics of the target battery string 10, thereby determining whether the target battery string 10 has a reverse overvoltage fault, and can also obtain the conduction state of the bypass diode D1. The method for determining whether the bypass diode D1 is conducting can be to detect whether the voltage across the bypass diode D1 is about 0.4 volts in the forward direction. Then, the controllable switch S on the shunt branch 20 is controlled to be closed when the target battery string 10 has a reverse overvoltage fault and the bypass diode D1 is in a non-conducting state.

[0063] In this embodiment, by setting up a reverse overvoltage detection component 30, it is possible to detect the reverse overvoltage characteristics of the target battery string 10. By setting up a processor 40, it is possible to control the shunt branch 20 to conduct when a reverse overvoltage fault occurs in the target battery string 10 and the bypass diode D1 is in a non-conducting state, so as to shunt the target battery string 10.

[0064] In one embodiment, as shown in FIG3 , the reverse overvoltage detection component includes: a current sensor 31 . The current sensor 31 is connected to the target battery string 10 and is used to collect the current of the target battery string 10 .

[0065] The processor 40 is connected to the current sensor 31 and is used to determine that a reverse overvoltage fault occurs in the target battery string 10 when the current of the target battery string 10 is less than a current threshold.

[0066] Among them, when the target battery string 10 has a reverse overvoltage fault, it is equivalent to a large resistor, so the current of the target battery string 10 will drop significantly. Therefore, when the current of the target battery string 10 is less than the current threshold, it is determined that the target battery string 10 has a reverse overvoltage fault.

[0067] In this embodiment, by providing the current sensor 31 , it is possible to identify whether the target battery string 10 has a reverse overvoltage fault.

[0068] In one embodiment, as shown in FIG4 , the reverse overvoltage detection component includes a temperature sensor 32 . The temperature sensor 32 is used to collect the temperature of the target battery string 10 .

[0069] The processor 40 is connected to the temperature sensor 32 , and is further configured to determine that a reverse overvoltage fault occurs in the target battery string 10 when the temperature of the target battery string 10 is greater than a temperature threshold.

[0070] Among them, when the target battery string 10 has a reverse overvoltage fault, it is equivalent to a large resistor, so the temperature of the target battery string 10 will increase significantly. Therefore, when the temperature of the target battery string 10 is greater than the temperature threshold, it is determined that the target battery string 10 has a reverse overvoltage fault.

[0071] In this embodiment, by providing the temperature sensor 32 , it is possible to identify whether the target battery string 10 has a reverse overvoltage fault.

[0072] In one embodiment, as shown in FIG5 , the reverse overvoltage detection component includes: an image sensor 33 . The image sensor 33 is used to capture a surface image of the target battery string 10 .

[0073] The processor 40 is connected to the image sensor 33 , and is further configured to determine whether a reverse overvoltage fault occurs in the target battery string 10 based on the surface image of the target battery string 10 .

[0074] The battery string 10 is a solar cell. When a portion of the surface of the battery string 10 is blocked, its power generation efficiency will be reduced, and a reverse overvoltage fault will occur. Therefore, by using the image sensor 33 (such as a smart camera) to capture the surface image of the target battery string 10, and then the processor 40 recognizes the image, it can be determined whether the surface of the battery string 10 is blocked, and then determine whether the target battery string 10 has a reverse overvoltage fault.

[0075] In this embodiment, by providing the image sensor 33 , it is possible to identify whether the target battery string 10 has a reverse overvoltage fault.

[0076] In one embodiment, as shown in FIG. 5 a , the protection circuit further includes: an alarm component 50 .

[0077] The alarm component 50 is connected to the processor 40 .

[0078] The processor 40 is used to send an alarm instruction to the alarm component 50 to make the alarm component 50 output an alarm signal when determining that the target battery string 10 is in a reverse overvoltage state.

[0079] In this embodiment, by setting an alarm component, when the target battery string 10 is in a reverse overvoltage state, an alarm signal can be issued to notify the user to handle it, so that the user can be informed in time and clear the fault of the target battery string 10 in time to protect the target battery string 10.

[0080] In one embodiment, as shown in FIG. 6 , a junction box 100 for a photovoltaic module is provided, comprising: at least one protection circuit according to any one of the above embodiments.

[0081] The junction box 100 may be a three-part junction box, and a shunt branch 20 may be connected in parallel to the bypass diode D1 in a conventional three-part junction box.

[0082] In this embodiment, the junction box also has the beneficial effects of the protection circuit in the above-mentioned embodiment. The similarities can be understood by referring to the above explanation of the protection circuit, which will not be repeated below.

[0083] In one embodiment, as shown in FIG. 7 , a photovoltaic assembly 200 is provided, comprising a plurality of battery strings 10 and a protection circuit as in any of the above embodiments, wherein the plurality of battery strings 10 are sequentially connected in series.

[0084] In this embodiment, the photovoltaic module also has the beneficial effects of the protection circuit in the above-mentioned embodiment. The similarities can be understood by referring to the above explanation of the protection circuit, which will not be repeated below.

[0085] In one embodiment, as shown in FIG8 , a photovoltaic module includes a plurality of battery string groups 300 , wherein the battery string groups 300 include a first battery string 301 and a second battery string 302 , wherein the first battery strings 301 of the plurality of battery string groups 300 are connected in series in sequence, and the second battery strings 302 of the plurality of battery string groups 300 are connected in parallel with the first battery strings 301 .

[0086] The first end of the bypass diode D1 and the shunt branch 20 connected in parallel is connected to the first end of the target battery string group 300, and the second end of the bypass diode D1 and the shunt branch 20 connected in parallel is connected to the second end of the target battery string group 300. The target battery string group 300 is one of the first battery string 301 and the second battery string 302 of the multiple battery string groups 300.

[0087] The shunt branch 20 is used to conduct the path between the first end and the second end of the target battery string group 300 when the target battery string group 300 is in a reverse overvoltage state and the bypass diode D1 is not conducting.

[0088] The battery string group 300 is obtained by connecting two battery strings 10 in parallel, and the target battery string group 300 is in a reverse overvoltage state, which means that at least a part of the two battery strings 10 is blocked. Other principles are the same as those in the above embodiment and will not be repeated.

[0089] For example, as shown in FIG9 , it is a schematic diagram of the structure of a photovoltaic module, showing a schematic diagram of a photovoltaic module being slightly blocked. It can be seen that one of the cells in the battery string 10 in FIG9 is blocked to a small extent. The reverse voltage caused by this degree of blocking is not enough to turn on the bypass diode D1, and the bypass diode D1 cannot be used for shunting. At this time, the shunt branch 20 needs to be turned on for shunting. When the cell is not blocked, the loop current I=I1. When the cell is blocked, the loop current I=I2. At this time, the blocked cell changes from a power source to a load, which is equivalent to inserting a large resistor in series in the battery array. I2 is significantly lower than I1, which will affect the power generation of the entire battery array. However, when the bypass diode D1 is turned on, or the shunt branch 20 is turned on, the battery string 10 where the obstructed battery cell is located will be bypassed, and the loop current I=I3 will almost completely flow through the shunt branch 20 or the bypass diode D1. At this time, the current level of the entire battery array can still be maintained at a relatively high level, that is, I3 is slightly lower than I1, and the voltage only loses the output voltage of one battery string 10. At this time, the voltage value of the battery string 10 will be clamped at about 0.4V due to the diode conduction. In addition, the communication function of the present application will promptly remind the user of component abnormalities, and the shunt branch 20 can be manually turned off after the user clears the obstruction.

[0090] As shown in FIG10, the current-voltage curve (IV curve) of the entire battery array when the battery cell is blocked and unblocked is shown. The ABDE curve in the figure is the IV curve when the battery cell is not blocked, and ABCE is the IV curve when the battery cell is blocked. The IV curve when the battery cell is blocked is now discussed in sections. In the AB section, the curves of the unblocked battery cell and the blocked battery cell overlap. Although the battery cell is blocked, the load has a low current requirement, so the blocked battery cell will not have a reverse voltage bias at this time, and can output power like a normal battery cell. In the BC section, the current of the blocked battery cell cannot meet the load current requirement, and a reverse voltage begins to appear on the battery cell (as long as the battery cell is blocked, the voltage will reverse, which is a characteristic), but the reverse voltage is not enough to turn on the bypass diode D1. At this time, the output current of the photovoltaic module will be pulled down from the normal DE section to the BC section, which will further cause the current level of the entire photovoltaic array to be pulled down. The present invention mainly solves the problem of lowering the current in this section. When the photovoltaic module operates in the BC section, the shunt branch 20 is turned on to bypass the blocked cell, so that the current level of the remaining unblocked cells is restored to the DE section. In the CE section, the reverse pressure of the blocked cell at point C can turn on the bypass diode D1. The CE section diode has been started, the current has returned to a normal level, and the voltage has dropped from the original BD section to the CE section. In the present invention, if the module operates in the CE section or to the left of point E (if the voltage is not greater than the voltage at point E, then the output current is fine and there is no need to interfere with the circuit), the shunt branch 20 does not need to be turned on, and the bypass diode D1 will be turned on.

[0091] In this embodiment, a photovoltaic assembly is provided, which can achieve the beneficial effects of the protection circuit in the above-mentioned embodiment. The similarities can be understood by referring to the above explanation of the protection circuit, and will not be repeated below.

[0092] In the description of this specification, the descriptions with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc., mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the utility model. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0093] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A protection circuit for a photovoltaic module, characterized in that: The photovoltaic assembly includes a plurality of battery strings, which are sequentially connected in series. The protection circuit includes: a bypass diode and a shunt branch, wherein the bypass diode and the shunt branch are connected in parallel. The first end of the bypass diode and the shunt branch connected in parallel is used to be connected to the first end of the target battery string of the photovoltaic assembly to be protected, and the second end of the bypass diode and the shunt branch connected in parallel is used to be connected to the second end of the target battery string, and the target battery string is one of the multiple battery strings; The shunt branch is used to conduct a path between the first end and the second end of the target battery string when the target battery string is in a reverse overvoltage state and the bypass diode is not conducting.

2. The protection circuit according to claim 1, characterized in that: The protection circuit further comprises: A reverse overvoltage detection component, used to detect a reverse overvoltage feature of the target battery string; The processor is connected to the reverse overvoltage detection component, the voltage sensor, and the shunt branch respectively, and is used to control the shunt branch to close so as to conduct the path between the first end and the second end of the target battery string when determining that the target battery string has a reverse overvoltage fault according to the reverse overvoltage characteristics of the target battery string and the bypass diode is in a non-conducting state.

3. The protection circuit according to claim 2, characterized in that: The reverse overvoltage detection component includes: a current sensor, which is connected to the target battery string and is used to collect the current of the target battery string; The processor is connected to the current sensor and is used to determine that a reverse overvoltage fault occurs in the target battery string when the current of the target battery string is less than a current threshold.

4. The protection circuit according to claim 2, characterized in that: The reverse overvoltage detection component includes: a temperature sensor, the temperature sensor is used to collect the temperature of the target battery string; The processor is connected to the temperature sensor, and is further configured to determine that a reverse overvoltage fault occurs in the target battery string when the temperature of the target battery string is greater than a temperature threshold.

5. The protection circuit according to claim 2, characterized in that: The reverse overvoltage detection component includes: an image sensor, the image sensor is used to capture a surface image of the target battery string; The processor is connected to the image sensor, and is further configured to determine whether a reverse overvoltage fault occurs in the target battery string according to the surface image of the target battery string.

6. The protection circuit according to claim 2, characterized in that: The protection circuit further comprises: an alarm component connected to the processor; The processor is used for sending an alarm instruction to the alarm component to make the alarm component output an alarm signal when determining that the target battery string is in a reverse overvoltage state.

7. The protection circuit according to any one of claims 1 to 6, characterized in that: The shunt branch includes: a controllable switch, and the controllable switch includes one of a relay, a metal-oxide semiconductor field effect transistor, an insulated gate bipolar transistor, a power transistor, and a gate turn-off thyristor.

8. A junction box for a photovoltaic module, characterized in that: include: At least one protection circuit as claimed in any one of claims 1 to 7.

9. A photovoltaic module, characterized in that: The invention comprises a plurality of battery strings and a protection circuit as claimed in any one of claims 1 to 7, wherein the plurality of battery strings are connected in series in sequence.

10. The photovoltaic module according to claim 9, characterized in that: The photovoltaic assembly includes a plurality of battery string groups, the battery string groups include a first battery string and a second battery string, the first battery strings of the plurality of battery string groups are sequentially connected in series, and the second battery strings of the plurality of battery string groups are connected in parallel with the first battery strings; The first end of the bypass diode and the shunt branch connected in parallel is connected to the first end of the target battery string group, and the second end of the bypass diode and the shunt branch connected in parallel is connected to the second end of the target battery string group, and the target battery string group is one of the first battery string or the second battery string of the multiple battery string groups; The shunt branch is used to conduct a path between the first end and the second end of the target battery string group when the target battery string group is in a reverse overvoltage state and the bypass diode is not conducting.

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