Photovoltaic module with protection against hot spots

Abstract

The utility model relates to photovoltaic module technical field especially a kind of photovoltaic module of false solder hot spot prevention, including photovoltaic cell string and junction box, the quantity of junction box is 2 or more, the connection of photovoltaic cell string and corresponding junction box, for output current, junction box has bypass diode in, junction box is connected in series through the series connection cable outside photovoltaic module between, photovoltaic cell string is connected in series with the photovoltaic cell string connected on other junction box by corresponding junction box. Advantageous effect is: when false solder occurs, corresponding photovoltaic cell string will be disconnected from the main circuit of output current, so as to avoid the photovoltaic cell string of this string to have shadow obstruction because of hot spot high temperature and damage photovoltaic module, even lead to photovoltaic module fire, and component safety is greatly improved;Meanwhile, the current of photovoltaic module passes through the bypass diode of corresponding junction box, does not affect other photovoltaic cell string and photovoltaic module power generation.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic module technology, and in particular to a photovoltaic module that prevents cold solder joints and hot spots. Background Technology

[0002] Whether it's a fully series-connected photovoltaic (PV) module or a series-parallel PV module with the upper and lower parts connected in parallel and then in series, the PV cell strings inside the PV module are all connected in series through the internal circuitry of the PV module. The PV cell strings are then welded to the leads of bypass diodes in the junction box via busbars extending from inside the PV module.

[0003] When shading occurs, the shaded photovoltaic (PV) cell strings can develop hot spots and high temperatures. Existing PV modules protect the shaded PV cell strings connected to the junction box by bypassing diodes in the junction box, preventing hot spots from forming.

[0004] When the photovoltaic cell string is properly connected to the junction box, the temperature of the hot spot is controllable and will not cause damage or fire to the photovoltaic module.

[0005] However, in reality, the welding connection structure between photovoltaic (PV) cell strings and junction boxes is not always reliable. The industry's welding reliability rate varies between 99% and 99.9%. When a hot spot problem occurs in a PV cell string within a PV module, if the corresponding solder joint of that string happens to be poorly soldered, the PV cell string will lack bypass diode protection. The shaded PV cells will generate higher temperatures, and prolonged high temperatures from the hot spot can lead to delamination and poor soldering within the PV module. In more severe cases, it can even cause the PV module to catch fire. There have been numerous cases in the industry of PV module damage and fires caused by poor soldering. Utility Model Content

[0006] The technical problem this invention aims to solve is that existing photovoltaic modules suffer from poor soldering between the photovoltaic cell string and the junction box, causing the poorly soldered photovoltaic cell string to lose the protection of the bypass diode.

[0007] The technical solution adopted by this utility model to solve its technical problem is: a photovoltaic module for preventing cold solder joints and hot spots, including photovoltaic cell strings inside the photovoltaic module and junction boxes on the back of the photovoltaic module. The number of junction boxes is two or more. The connection between the photovoltaic cell strings and the corresponding junction boxes is used for output current. The junction boxes have bypass diodes for bypass protection of the photovoltaic cell strings connected to the junction boxes. The junction boxes are connected in series through series cables outside the photovoltaic module. The photovoltaic cell strings are connected in series with the photovoltaic cell strings connected to other junction boxes through the corresponding junction boxes.

[0008] In some embodiments, optionally, the photovoltaic module for preventing cold solder joint hot spots further includes a positive terminal cable and a negative terminal cable, which serve as the positive and negative output terminals of the photovoltaic module. The positive terminal cable is connected to the junction box at the positive terminal end of each junction box connected in series, and the negative terminal cable is connected to the junction box at the negative terminal end of each junction box connected in series.

[0009] In some embodiments, optionally, the junction box has a main circuit output terminal M, a battery string input terminal N, a main circuit connection circuit, and a bypass diode. The battery string input terminal N is used to connect to the corresponding photovoltaic cell string, the main circuit output terminal M is used to output the current of the corresponding photovoltaic cell string, the battery string input terminal N and the main circuit output terminal M are connected through the main circuit connection circuit, the bypass diode is connected in parallel between the positive and negative lines of the main circuit connection circuit, and the series cable is connected to the main circuit output terminal M for connecting the junction box in series.

[0010] In some embodiments, optionally, the photovoltaic module for preventing cold solder joint hot spots further includes a positive terminal cable and a negative terminal cable, used as the positive and negative output terminals of the photovoltaic module. The number of junction boxes is three or more. The junction box at the positive terminal end of each junction box connected in series is the positive terminal box, the junction box at the negative terminal end of each junction box connected in series is the negative terminal box, and the junction box between the positive terminal box and the negative terminal box is the intermediate terminal box. The positive terminal of the main circuit output terminal M of the positive terminal box is connected to the positive terminal cable, and the negative terminal of the main circuit output terminal M of the positive terminal box is connected to the series cable. The positive and negative terminals of the main circuit output terminal M of the intermediate terminal box are respectively connected to the series cables on both sides. The positive terminal of the main circuit output terminal M of the negative terminal box is connected to the series cable, and the negative terminal of the main circuit output terminal M of the negative terminal box is connected to the negative terminal cable.

[0011] The beneficial effects of this utility model are: by connecting photovoltaic cell strings in series through the series cables between junction boxes, when a poor solder joint occurs, the corresponding photovoltaic cell string will be disconnected from the main circuit of the output current, thereby avoiding damage to the photovoltaic module due to the high temperature of hot spots when the photovoltaic cell string is shaded, or even causing the photovoltaic module to catch fire, thus greatly improving the safety of the module.

[0012] Meanwhile, the current of the photovoltaic module passes through the bypass diode of the corresponding junction box, without affecting the power generation of other photovoltaic cell strings and photovoltaic modules. Attached Figure Description

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0014] Figure 1 This is a schematic diagram of the circuit principle of an existing photovoltaic module;

[0015] Figure 2 This is a schematic diagram of the front structure of an existing photovoltaic module;

[0016] Figure 3 This is a schematic diagram of the back structure of an existing photovoltaic module;

[0017] Figure 4 This is a schematic diagram of the circuit structure of the series junction box of this utility model;

[0018] Figure 5 This is a schematic diagram of the front structure of the photovoltaic module of this utility model;

[0019] Figure 6 This is a schematic diagram of the back structure of the photovoltaic module of this utility model;

[0020] Figure 7 This is a schematic diagram of the circuit principle of this utility model.

[0021] In the diagram, 1. Photovoltaic cell string, 2. Junction box, 2-1. Positive terminal junction box, 2-2. Intermediate terminal junction box, 2-3. Negative terminal junction box, 3. Bypass diode, 4. Series cable, 5. Positive terminal cable, 6. Negative terminal cable. Detailed Implementation

[0022] like Figures 4-7 As shown, a photovoltaic module for preventing cold solder joint hot spots includes photovoltaic cell strings 1 inside the photovoltaic module and junction boxes 2 on the back of the photovoltaic module. The number of junction boxes 2 is two or more. The connection between the photovoltaic cell strings 1 and the corresponding junction boxes 2 is used for output current. The junction box 2 has a bypass diode 3 for bypass protection of the photovoltaic cell strings 1 connected to the junction box 2. The junction boxes 2 are connected in series with each other through a series cable 4 outside the photovoltaic module. The photovoltaic cell strings 1 are connected in series with the photovoltaic cell strings 1 connected to other junction boxes 2 through the corresponding junction boxes 2.

[0023] Junction box 2 has a main circuit output terminal M, a battery string input terminal N, a main circuit connection circuit, and a bypass diode 3. The battery string input terminal N is used to connect to the corresponding photovoltaic cell string 1. The main circuit output terminal M is used to output the current of the corresponding photovoltaic cell string 1. The battery string input terminal N and the main circuit output terminal M are connected through the main circuit connection circuit. The bypass diode 3 is connected in parallel between the positive and negative lines of the main circuit connection circuit. The series cable 4 is connected to the main circuit output terminal M and is used to connect junction box 2 in series.

[0024] The photovoltaic module for preventing hot spots from poor soldering also includes a positive terminal cable 5 and a negative terminal cable 6, which are used as the positive and negative output terminals of the photovoltaic module. The positive terminal cable 5 is connected to the positive terminal of each terminal box 2 connected in series, and the negative terminal cable 6 is connected to the negative terminal of each terminal box 2 connected in series.

[0025] When there are 3 or more junction boxes 2, the junction box 2 at the positive end of each junction box 2 connected in series is called positive junction box 2-1, the junction box 2 at the negative end of each junction box 2 connected in series is called negative junction box 2-3, and the junction box 2 between positive junction box 2-1 and negative junction box 2-3 is called intermediate junction box 2-2. The positive terminal of the main circuit output terminal M of positive junction box 2-1 is connected to the positive terminal cable 5, and the negative terminal of the main circuit output terminal M of positive junction box 2-1 is connected to the series cable 4. The positive and negative terminals of the main circuit output terminal M of intermediate junction box 2-2 are connected to the series cables 4 on both sides respectively. The positive terminal of the main circuit output terminal M of negative junction box 2-3 is connected to the series cable 4, and the negative terminal of the main circuit output terminal M of negative junction box 2-3 is connected to the negative terminal cable 6.

[0026] The various junction boxes 2 connected in series form the main circuit for output current.

[0027] like Figure 1 , 2 As shown in Figure 3, the existing 6-string split-parallel photovoltaic module contains 6 photovoltaic cell strings 1, divided into upper and lower parts, with 3 strings in each part. The upper photovoltaic cell string 1 and the corresponding lower photovoltaic cell string 1 are both welded to the same junction box 2, so that these two photovoltaic cell strings 1 are connected in parallel to form one photovoltaic cell string group, forming three photovoltaic cell string groups: left, middle, and right. Figure 1 The three photovoltaic cell strings on the left, middle, and right are connected to the negative terminal junction box 2-3, the middle terminal junction box 2-2, and the positive terminal junction box 2-1, respectively. These three photovoltaic cell strings are directly connected in series within the photovoltaic module via a busbar. There are three independent junction boxes 2 on the back of the photovoltaic module.

[0028] like Figure 4 , 5 As shown in Figures 6 and 7, similar to existing 6-string split-parallel photovoltaic modules, in this embodiment, the number of photovoltaic cell strings 1 within the photovoltaic module is also 6, divided into upper and lower parts, with 3 strings in each part. There are 3 junction boxes 2. The upper part's photovoltaic cell string 1 and the corresponding lower part's photovoltaic cell string 1 are both welded to the same junction box 2, so that these two photovoltaic cell strings 1 are connected in parallel to form one photovoltaic cell string group, forming three photovoltaic cell string groups: left, middle, and right. Figure 7 The three photovoltaic cell strings in the middle, left, center, and right are respectively connected to the negative terminal junction box 2-3, the middle terminal box 2-2, and the positive terminal junction box 2-1.

[0029] Unlike existing series-parallel photovoltaic modules, in this embodiment, the three photovoltaic cell strings on the left, middle, and right are disconnected inside the photovoltaic module, and are connected in series via the series cable 4 between the junction boxes 2.

[0030] The number of junction boxes 2 is related to the number of photovoltaic cell strings. If there are 4 photovoltaic cell strings in the photovoltaic module, then there are also 4 junction boxes 2.

[0031] The working principle of this embodiment is as follows:

[0032] The soldering points on the six battery string connection terminals N of the three junction boxes 2 are, from left to right, the first solder point, the second solder point, the third solder point, the fourth solder point, the fifth solder point, and the sixth solder point. When all six solder points are normal, it is the same as existing photovoltaic modules.

[0033] When the first or sixth solder joint is poorly soldered, similar to existing photovoltaic modules, the left or right photovoltaic cell string is disconnected from the main circuit of the output current. The current of the other photovoltaic cell strings passes through the bypass diode 3 in the corresponding junction box 2, i.e., positive junction box 2-1 or negative junction box 2-3. At this time, even if there is shading, no hot spot high temperature will be generated.

[0034] When one or more of the second to fifth solder joints experience a cold solder joint, in the prior art, the corresponding photovoltaic cell string 1 would lose the protection of the bypass diode 3. However, in this embodiment, because the three photovoltaic cell strings within the photovoltaic module need to be connected to the main circuit for output current through solder joints, a cold solder joint means that this photovoltaic cell string is disconnected from the main circuit for output current. Therefore, even if this photovoltaic cell string is shaded, hot spot high temperature will not occur. The current of other photovoltaic cell strings 1 passes through the bypass diode 3 in the cold solder joint junction box 2, without affecting the power generation of other photovoltaic cell strings 1 and the photovoltaic module.

[0035] exist Figure 2 and Figure 5 The frame around the photovoltaic module is omitted.

[0036] In this utility model, the technical term "more than 2" includes 2, and "more than 3" includes 3.

Claims

1. A photovoltaic module for preventing cold solder joint hot spots, characterized in that: The photovoltaic module includes a photovoltaic cell string (1) inside the photovoltaic module and a junction box (2) on the back of the photovoltaic module. There are two or more junction boxes (2). The connection between the photovoltaic cell string (1) and the corresponding junction box (2) is used to output current. The junction box (2) has a bypass diode (3) for bypass protection of the photovoltaic cell string (1) connected to the junction box (2). The junction boxes (2) are connected in series with each other through a series cable (4) outside the photovoltaic module. The photovoltaic cell string (1) is connected in series with the photovoltaic cell string (1) connected to other junction boxes (2) through the corresponding junction box (2).

2. The photovoltaic module for preventing cold solder joints and hot spots according to claim 1, characterized in that: It also includes a positive terminal cable (5) and a negative terminal cable (6) for use as the positive and negative output terminals of the photovoltaic module. The positive terminal cable (5) is connected to the positive terminal of each terminal box (2) in series, and the negative terminal cable (6) is connected to the negative terminal of each terminal box (2) in series.

3. The photovoltaic module for preventing cold solder joint hot spots according to claim 1, characterized in that: The junction box (2) has a main circuit output terminal M, a battery string input terminal N, a main circuit connection circuit and a bypass diode (3). The battery string input terminal N is used to connect with the corresponding photovoltaic cell string (1). The main circuit output terminal M is used to output the current of the corresponding photovoltaic cell string (1). The battery string input terminal N and the main circuit output terminal M are connected through the main circuit connection circuit. The bypass diode (3) is connected in parallel between the positive and negative lines of the main circuit connection circuit. The series cable (4) is connected to the main circuit output terminal M and is used to connect the junction box (2) in series.

4. The photovoltaic module for preventing cold solder joint hot spots according to claim 3, characterized in that: It also includes a positive terminal cable (5) and a negative terminal cable (6) for use as the positive and negative output terminals of the photovoltaic module. The number of junction boxes (2) is more than three. The junction box (2) at the positive terminal end of each junction box (2) connected in series is the positive terminal junction box (2-1), the junction box (2) at the negative terminal end of each junction box (2) connected in series is the negative terminal junction box (2-3), and the junction box (2) between the positive terminal junction box (2-1) and the negative terminal junction box (2-3) is the intermediate junction box (2-2). The positive terminal of the main circuit output terminal M of the positive terminal junction box (2-1) is connected to the positive terminal cable (5), the negative terminal of the main circuit output terminal M of the positive terminal junction box (2-1) is connected to the series cable (4), the positive and negative terminals of the main circuit output terminal M of the intermediate terminal junction box (2-2) are respectively connected to the series cables (4) on both sides, the positive terminal of the main circuit output terminal M of the negative terminal junction box (2-3) is connected to the series cable (4), and the negative terminal of the main circuit output terminal M of the negative terminal junction box (2-3) is connected to the negative terminal cable (6).

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