A bypass diode circuit assembly with temperature protection

Abstract

The utility model discloses a bypass diode circuit component with temperature protection for parallel connection with photovoltaic cell component, and the photovoltaic cell component includes a plurality of mutually series connection's photovoltaic cell group, and the bypass diode circuit component with temperature protection includes substrate, thermosensitive device and a plurality of bypass diode for parallel connection in photovoltaic cell group both ends, thermosensitive device and a plurality of bypass diode set up in substrate, and thermosensitive device is close to a plurality of bypass diode setting, bypass diode anode is used for connecting the negative pole of parallel connection's photovoltaic cell group, and bypass diode cathode is used for connecting the positive pole of parallel connection's photovoltaic cell group, and thermosensitive device sets up in the loop of bypass diode and load constitution, and thermosensitive device has the resistance value of positive temperature coefficient, when temperature rises to threshold value, thermosensitive device disconnects, and when temperature drops to recovery threshold value, thermosensitive device reconducts. The utility model can avoid that photovoltaic cell component and bypass diode burn because of the continuous high temperature.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic technology, and in particular to a bypass diode circuit assembly with temperature protection. Background Technology

[0002] A bypass diode is a diode connected in reverse parallel to both ends of a photovoltaic cell array in a photovoltaic cell module. It can effectively prevent silicon cells from burning out due to hot spot effect. It is an important component of photovoltaic cell modules and can prevent some photovoltaic cells from becoming loads due to lack of light under strong light, resulting in serious heat generation and damage.

[0003] For the operating principle of the bypass diode in the prior art, please refer to [link / reference]. Figure 1 The photovoltaic cell module includes multiple photovoltaic cell groups (C1, C2) connected in series, and bypass diodes (D1, D2) are connected in parallel with each photovoltaic cell group (C1, C2). Figure 1 In Figure (a), the photovoltaic cell arrays C1 and C2 are exposed to the same amount of light, and the load is powered by both photovoltaic cell arrays C1 and C2. The bypass diodes (D1, D2) are not conducting. Figure 1 In (b), the illumination of photovoltaic cell array C1 is greater than that of photovoltaic cell array C2. The load is powered by photovoltaic cell array C1 and is connected via a bypass formed by diode D2. Figure 1 In the case of (c), the illumination of photovoltaic cell array C1 is less than that of photovoltaic cell array C2. The load is powered by photovoltaic cell array C2 and is connected via a bypass formed by diode D1.

[0004] Commonly used photovoltaic (PV) module bypass circuits are typically installed in a junction box at the bottom of the PV module. Copper strips are led out from inside the PV module to connect the cell strings to the bypass diodes. While this installation meets functional requirements, it doesn't satisfy the needs of certain applications, such as rooftop installations in RVs where lightweight, flat, and flexible modules are required. To address these needs, an ultra-thin bypass diode circuit assembly is needed, which can be embedded within a lightweight, flexible panel, flush with the silicon solar cells. However, this structure leads to poor heat dissipation during operation, increasing the risk of thermal runaway and damage.

[0005] In view of this, it is necessary to propose a new bypass diode circuit assembly to improve the above-mentioned problems. Utility Model Content

[0006] The purpose of this invention is to provide a bypass diode circuit assembly with temperature protection, which can prevent photovoltaic cell assembly and bypass diode from burning out due to continuous high temperature.

[0007] This utility model provides the following solution:

[0008] This invention proposes a bypass diode circuit assembly with temperature protection for parallel connection with a photovoltaic cell assembly. The photovoltaic cell assembly includes several photovoltaic cell groups connected in series. The bypass diode circuit assembly with temperature protection includes a substrate, a thermistor, and multiple bypass diodes connected in parallel across the two ends of the photovoltaic cell groups. The thermistor and the multiple bypass diodes are disposed on the substrate, with the thermistor positioned close to the multiple bypass diodes. The anode of the bypass diode is connected to the negative terminal of the parallel-connected photovoltaic cell group, and the cathode of the bypass diode is connected to the positive terminal of the parallel-connected photovoltaic cell group. The thermistor is disposed in the circuit formed by the bypass diodes and the load. The thermistor has a resistance value with a positive temperature coefficient. When the temperature rises to a threshold value, the thermistor disconnects; when the temperature drops to a recovery threshold value, the thermistor reconnects.

[0009] Optionally, the plurality of bypass diodes are connected in series and in parallel.

[0010] Optionally, the substrate is provided with a photovoltaic module positive terminal interface, a photovoltaic module negative terminal interface, a load negative terminal interface, and at least one photovoltaic cell string interface; the photovoltaic module positive terminal interface is connected to the cathode of a bypass diode for parallel connection with the first photovoltaic cell string, and the photovoltaic module positive terminal interface is used to connect the positive terminal of the photovoltaic module and the positive terminal of the load; the photovoltaic module negative terminal interface is connected to the anode of a bypass diode for parallel connection with the last photovoltaic cell string, and the photovoltaic module negative terminal interface is used to connect the negative terminal of the photovoltaic module; the load negative terminal interface is connected to the thermistor, and the load negative terminal interface is used to connect the negative terminal of the load; the photovoltaic cell string interface is connected to the series connection point between the bypass diodes, and the photovoltaic cell string interface is used to connect the series connection point between the photovoltaic cell strings.

[0011] Optionally, the photovoltaic module includes photovoltaic cell array C1 and photovoltaic cell array C2, and the plurality of bypass diodes include diodes D1, D2, D3, and D4; the positive terminal interface of the photovoltaic module is connected to the cathodes of diodes D1 and D2, the photovoltaic cell array string interface is connected to the anodes of diodes D1, D2, D3, and D4, the negative terminal interface of the photovoltaic module is connected to the anodes of diodes D3 and D4 and one end of a thermistor, and the negative terminal interface of the load is connected to the other end of the thermistor; the positive terminal interface of the photovoltaic module is used to connect the positive terminal of photovoltaic cell array C1 to the positive terminal of the load, the photovoltaic cell array string interface is used to connect the negative terminal of photovoltaic cell array C1 to the positive terminal of photovoltaic cell array C2, and the negative terminal interface of the photovoltaic module is used to connect the negative terminal of photovoltaic cell array C2.

[0012] Optionally, the positive terminal interface, negative terminal interface, load negative terminal interface, and photovoltaic cell string interface of the photovoltaic cell module are all openings provided on the substrate.

[0013] Optionally, the diodes D1, D2, D3, D4 and the thermistor are disposed on the same side of the substrate.

[0014] Optionally, diodes D1, D2, D3, and D4 are arranged around the thermistor.

[0015] Optionally, the plurality of bypass diodes are connected in series.

[0016] Optionally, the thermistor is a polymer positive temperature coefficient thermistor.

[0017] Optionally, the substrate is an ultrathin substrate.

[0018] This utility model has the following advantages compared with the prior art:

[0019] This invention discloses a bypass diode circuit assembly with temperature protection. When some cells of a photovoltaic (PV) module are shaded during operation, the current generated by the PV module connects to the load through a portion of the bypass diode and a thermistor. As the temperature of the partially conducting bypass diode rises, the temperature and resistance of the nearby thermistor increase, suppressing the increase in load current. The PV system then derating its output and maintaining stability. Furthermore, when the bypass diode temperature continues to rise and reaches a threshold, the thermistor disconnects, cutting off the connection to the load. No more current flows through the bypass diode, and its temperature slowly decreases. When the temperature drops to a recovery threshold, the thermistor closes again, and the PV module resumes power output. This process can repeat, thus controlling the high temperature of the PV module and bypass diode within a manageable range, protecting them from burnout due to sustained high temperatures. In addition, this invention also features a slim and lightweight overall design, meeting the needs of specific applications such as rooftop installation in RVs. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the operating principle of the bypass diode in the prior art, wherein (a) is a schematic diagram of the principle when the illumination of photovoltaic cell group C1 and photovoltaic cell group C2 is the same, (b) is a schematic diagram of the principle when the illumination of photovoltaic cell group C1 is greater than that of photovoltaic cell group C2, and (c) is a schematic diagram of the principle when the illumination of photovoltaic cell group C1 is less than that of photovoltaic cell group C2.

[0022] Figure 2 This is a schematic diagram illustrating the principle of multiple bypass diodes connected in parallel across both ends of a photovoltaic cell array.

[0023] Figure 3 This is a schematic diagram of the principle of this utility model, in which a bypass diode is connected in parallel at both ends of each photovoltaic cell array;

[0024] Figure 4 This is another schematic diagram of the principle of this utility model, in which a bypass diode is connected in parallel at both ends of each photovoltaic cell array;

[0025] Figure 5 This is a schematic diagram of the principle of the present invention, which has a photovoltaic cell module positive terminal interface, a photovoltaic cell module negative terminal interface, a load negative terminal interface and at least one photovoltaic cell string interface on the substrate.

[0026] Figure 6 This is a front view of the structure of the present invention, in which the positive terminal interface, negative terminal interface, load negative terminal interface and photovoltaic cell string interface are all provided in the openings of the substrate 210.

[0027] Figure 7 This is a side view of the structure of the present invention, in which the positive terminal interface, negative terminal interface, load negative terminal interface and photovoltaic cell string interface are all provided in the openings of the substrate 210.

[0028] In the picture:

[0029] 100 - Photovoltaic cell module; 200 - Bypass diode circuit assembly with temperature protection; substrate 210; 211 - Positive terminal interface of photovoltaic cell module; 212 - Negative terminal interface of photovoltaic cell module; 213 - Negative terminal interface of load; 214 - String interface of photovoltaic cell; 300 - Load. Detailed Implementation

[0030] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0031] See Figures 2 to 7 This invention proposes an embodiment of a bypass diode circuit assembly 200 with temperature protection, used in parallel with a photovoltaic cell assembly 100, which includes several photovoltaic cell groups (C1, C2) connected in series. The bypass diode circuit assembly 200 with temperature protection includes a substrate 210, a thermistor R1, and multiple bypass diodes (D1, D2, D3, D4) for parallel connection across the photovoltaic cell groups (C1, C2). The thermistor R1 and the multiple bypass diodes (D1, D2, D3, D4) are disposed on the substrate 210, with the thermistor R1 positioned close to the multiple bypass diodes (D1, D2, D3, D4). The anode of the bypass diodes (D1, D2, D3, D4) is connected to the negative terminal of the parallel-connected photovoltaic cell group, and the cathode of the bypass diodes (D1, D2, D3, D4) is connected to the positive terminal of the parallel-connected photovoltaic cell group. Thermistor R1 is placed in the circuit formed by the bypass diodes (D1, D2, D3, D4) and the load 300. Thermistor R1 has a resistance value with a positive temperature coefficient. When the temperature rises to the threshold, thermistor R1 is turned off, and when the temperature drops to the recovery threshold, thermistor R1 is turned on again.

[0032] The working principle of this invention is as follows: When some cells of a photovoltaic module are shaded during operation, the voltage generated by several interconnected photovoltaic cell groups (C1, C2) becomes unbalanced. Some of the bypass diodes (D1, D2, D3, D4) conduct, and the current generated by the photovoltaic module connects to the load through these bypass diodes and the thermistor R1. However, when the ambient temperature is too high and the photovoltaic module is generating power at a high rate, the temperature of the partially conducting bypass diodes (D1, D2, D3, D4) rises, and the temperature and resistance of the nearby thermistor R1 increase, suppressing the increase in load current. This causes the photovoltaic system to derating and maintain stability. If the external environment does not permit it, the bypass diode temperature will continue to rise. When the temperature reaches the threshold, the thermistor R1 will disconnect, cutting off the connection to the load. No current will flow through the bypass diodes (D1, D2, D3, D4), and the temperature will slowly decrease. When the temperature drops to the recovery threshold, the thermistor R1 will close again, and the photovoltaic module will output power again. This process can repeat, thus controlling the high temperature of the photovoltaic module and bypass diodes within a manageable range, protecting them from burning out due to sustained high temperatures.

[0033] In some embodiments, see Figure 2 Multiple bypass diodes (D1, D2, D3, D4) are connected in series and parallel. Connecting multiple bypass diodes in parallel across a photovoltaic cell array (C1, C2) can shunt the current flowing through the bypass diodes, which can suppress overheating and damage.

[0034] In some embodiments, see Figure 3 and Figure 4 Multiple bypass diodes (D1, D3) are connected in series. This ensures that a bypass diode (D1, D3) is connected in parallel across each photovoltaic cell array (C1, C2). Figure 3 The thermistor R1 is connected to the negative terminal of the load 300. Figure 4 The medium-temperature sensitive device R1 is connected to the negative terminal of the load 300.

[0035] In some embodiments, see Figure 5The substrate 210 is provided with a photovoltaic module positive terminal interface 211, a photovoltaic module negative terminal interface 212, a load negative terminal interface 213, and at least one photovoltaic cell string interface 214. The photovoltaic module positive terminal interface 211 connects to the cathode of a bypass diode (D1, D2) for parallel connection with the first photovoltaic cell string C1, and is used to connect the positive terminal of the photovoltaic module 100 and the positive terminal of the load 300. The photovoltaic module negative terminal interface 212 connects to the anode of a bypass diode (D3, D4) for parallel connection with the last photovoltaic cell string C2, and is used to connect the negative terminal of the photovoltaic module 100. The load negative terminal interface 213 connects to a thermistor R1, and is used to connect the negative terminal of the load 300. The photovoltaic cell string interface 214 connects the series connection points between the bypass diodes (D1, D2, D3, D4) and is used to connect the series connection points between photovoltaic cell groups (C1, C2).

[0036] In this embodiment, the photovoltaic module positive terminal interface 211, photovoltaic module negative terminal interface 212, load negative terminal interface 213 and at least one photovoltaic cell string interface 214 provided on the substrate 210 facilitate connection with the photovoltaic module 100 and the load 300.

[0037] In some embodiments, see Figure 5 The photovoltaic module 100 includes photovoltaic cell arrays C1 and C2, and multiple bypass diodes including diodes D1, D2, D3, and D4. The positive terminal interface 211 of the photovoltaic module connects to the cathodes of diodes D1 and D2, the cell array string interface 214 connects to the anodes of diodes D1, D2, D3, and D4, the negative terminal interface 212 connects to the anodes of diodes D3 and D4 and one end of the thermistor R1, and the load negative terminal interface 213 connects to the other end of the thermistor R1. The positive terminal interface 211 connects the positive terminal of photovoltaic cell array C1 to the positive terminal of load 300, the cell array string interface 214 connects the negative terminal of photovoltaic cell array C1 to the positive terminal of photovoltaic cell array C2, the negative terminal interface 212 connects to the negative terminal of photovoltaic cell array C2, and the load negative terminal interface 213 connects to the negative terminal of load 300.

[0038] In this embodiment, diodes D1 and D2 are connected in parallel, and diodes D3 and D4 are connected in parallel, both of which can serve to shunt current and suppress the temperature rise of the bypass diodes.

[0039] In some embodiments, see Figure 6The photovoltaic module positive terminal interface 211, photovoltaic module negative terminal interface 212, load negative terminal interface 213 and photovoltaic cell string interface 214 are all openings provided on the substrate 210.

[0040] In some embodiments, see Figure 6 , Figure 7 Diodes D1, D2, D3, D4 and thermistor R1 are located on the same side of the substrate, which facilitates the placement of the devices and also allows thermistor R1 to accurately sense the temperature of the bypass diode.

[0041] In some embodiments, see Figure 6 , Figure 7 Diodes D1, D2, D3, and D4 are arranged around the thermistor R1 to facilitate the thermistor R1 in accurately sensing the temperature of the bypass diode.

[0042] In some embodiments, see Figures 2 to 7 The thermistor R1 is a polymer positive temperature coefficient thermistor (PPTC). In some specific implementations, the PPTC will disconnect when the bypass diode heats up to about 95°C, and will reconnect when the temperature drops back to 80°C.

[0043] In some embodiments, see Figure 6 , Figure 7 The substrate 210 is an ultra-thin substrate. In some specific embodiments, the thickness of the substrate 210 can be 1.2mm. The thermistor R1 and the bypass diode are both thin surface-mount devices, which takes into account the overall thinness of the component and can meet the needs of specific application scenarios, such as roof mounting in RVs.

[0044] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art and should not be interpreted in an idealized or overly formal sense unless specifically defined.

[0045] It should be noted that certain terms are used in this specification and claims to refer to specific elements. Those skilled in the art will understand that different manufacturers or producers may use different terms to refer to the same element. This specification and claims do not distinguish elements based on differences in terminology, but rather on differences in function.

[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0047] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this invention and form different embodiments. For example, any one of the embodiments claimed in the claims can be used in any combination of embodiments of this invention.

[0048] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the corresponding claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the corresponding claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A bypass diode circuit assembly with temperature protection, used in parallel with a photovoltaic cell assembly, the photovoltaic cell assembly comprising a plurality of photovoltaic cell groups connected in series, characterized in that, The bypass diode circuit assembly with temperature protection includes a substrate, a thermistor, and multiple bypass diodes for parallel connection across the photovoltaic cell array. The thermistor and the multiple bypass diodes are disposed on the substrate, with the thermistor positioned close to the multiple bypass diodes. The anode of the bypass diode is connected to the negative terminal of the parallel-connected photovoltaic cell array, and the cathode of the bypass diode is connected to the positive terminal of the parallel-connected photovoltaic cell array. The thermistor is disposed in the circuit formed by the bypass diodes and the load. The thermistor has a resistance value with a positive temperature coefficient. When the temperature rises to a threshold value, the thermistor disconnects; when the temperature drops to a recovery threshold value, the thermistor reconnects.

2. The bypass diode circuit assembly with temperature protection according to claim 1, characterized in that, The multiple bypass diodes are connected in series and in parallel.

3. A bypass diode circuit assembly with temperature protection according to any one of claims 1 or 2, characterized in that, The substrate is provided with a photovoltaic module positive terminal interface, a photovoltaic module negative terminal interface, a load negative terminal interface, and at least one photovoltaic cell string interface; the photovoltaic module positive terminal interface is connected to the cathode of a bypass diode for parallel connection with the first photovoltaic cell string, and the photovoltaic module positive terminal interface is used to connect the positive terminal of the photovoltaic module and the positive terminal of the load; the photovoltaic module negative terminal interface is connected to the anode of a bypass diode for parallel connection with the last photovoltaic cell string, and the photovoltaic module negative terminal interface is used to connect the negative terminal of the photovoltaic module; the load negative terminal interface is connected to the thermistor, and the load negative terminal interface is used to connect the negative terminal of the load; the photovoltaic cell string interface is connected to the series connection point between the bypass diodes, and the photovoltaic cell string interface is used to connect the series connection point between the photovoltaic cell strings.

4. A bypass diode circuit assembly with temperature protection according to claim 3, characterized in that, The photovoltaic module includes photovoltaic cell arrays C1 and C2. The plurality of bypass diodes include diodes D1, D2, D3, and D4. The positive terminal interface of the photovoltaic module is connected to the cathodes of diodes D1 and D2. The cell array string interface is connected to the anodes of diodes D1, D2, D3, and D4. The negative terminal interface of the photovoltaic module is connected to the anodes of diodes D3 and D4 and one end of a thermistor. The load negative terminal interface is connected to the other end of the thermistor. The positive terminal interface of the photovoltaic module is used to connect the positive terminal of photovoltaic cell array C1 to the positive terminal of the load. The cell array string interface is used to connect the negative terminals of photovoltaic cell array C1 and C2. The negative terminal interface of the photovoltaic module is used to connect the negative terminal of photovoltaic cell array C2.

5. A bypass diode circuit assembly with temperature protection according to claim 4, characterized in that, The positive terminal interface, negative terminal interface, load negative terminal interface, and photovoltaic cell string interface of the photovoltaic cell module are all openings provided on the substrate.

6. A bypass diode circuit assembly with temperature protection according to claim 4, characterized in that, The diodes D1, D2, D3, D4 and the thermistor are disposed on the same side of the substrate.

7. A bypass diode circuit assembly with temperature protection according to claim 6, characterized in that, Diodes D1, D2, D3, and D4 are arranged around the thermistor.

8. A bypass diode circuit assembly with temperature protection according to claim 1, characterized in that, The multiple bypass diodes are connected in series.

9. A bypass diode circuit assembly with temperature protection according to claim 1, characterized in that, The thermistor is a polymer positive temperature coefficient thermistor.

10. A bypass diode circuit assembly with temperature protection according to claim 1, characterized in that, The substrate is an ultra-thin substrate, and the thermistor and bypass diode are both thin-film surface mount devices.

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