Photovoltaic junction box

Abstract

The utility model belongs to the field of photovoltaic technology, in particular to a photovoltaic junction box, which comprises a box body and a box cover arranged at the top end of the box body. A transmission piece is arranged in the box body, a through hole is formed in the bottom of the box body, and the leading-out piece enters the box body from the through hole and is partially located above the transmission piece; a pair of welding assemblies is arranged on the upper surface of the conveying piece and used for fixing the leading-out pieces corresponding to the welding assemblies to the conveying piece. The welding assembly comprises a first welding piece and a second welding piece which are arranged in a spaced mode, the first welding piece or the second welding piece is a secondary welding piece, and a connecting piece is arranged on the upper surface of the secondary welding piece. According to the utility model, by adding the secondary welding piece and the connecting piece, when virtual connection or welding internal defects occur at the welding position of the leading-out piece, high temperature generated at the welding position is conducted to the secondary welding piece through the leading-out piece, so that the secondary welding piece is melted, and secondary welding with the leading-out piece is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of photovoltaics, in particular to a photovoltaic junction box. Background Art

[0002] As a connector for solar cell modules, the photovoltaic junction box mainly exports the electricity generated by the solar cell module to the load or the power grid through the cable. However, to achieve the connection between the two, the busbars led out of the solar cell module and the metal components in the photovoltaic junction box need to be welded together through a welding process. The current welding process is to use high temperature to heat the tin-lead solder attached to the metal components in the photovoltaic junction box, and press the busbars led out of the solar cell module so that the melted tin-lead solder is fully in contact with the busbars and wraps the busbars, thereby achieving welding. After the welding is completed, there are two ways to detect the welding quality. One is that the employee uses the tooling to lift the busbars led out of the solar cell module to observe whether it will be separated from the metal components in the junction box; the other is to use the CCD impact system to detect whether the tin-lead solder completely wraps the busbars led out of the solar cell module. Both of the above detection methods cannot detect defects inside the solder after welding, and both have the risk of missed detection, resulting in the flow of products with virtual connection between the busbars led out of the solar cell module and the metal components in the photovoltaic junction box to the power station.

[0003] Since solar cell modules work outdoors for a long time, under the action of thermal shock and mechanical stress, if there are internal defects in the solder, the busbars led out of the solar cell modules and the metal structure welding in the photovoltaic junction box are easy to separate or be loosely connected. If the two are separated, the internal circuit of the solar cell module is short-circuited, and the generated electricity cannot be extracted. If the two are loosely connected, the resistance at the welding position increases, generating a lot of heat, resulting in large leakage of the photovoltaic module diode, causing power loss and even burning the junction box and causing a fire. Utility Model Content

[0004] The present application provides a photovoltaic junction box to solve the technical problem in the related art that a bus bar led out from a solar cell module and a transmission member in the photovoltaic junction box are poorly connected or produce welding defects.

[0005] The present application provides a photovoltaic junction box, comprising a box body; a transmission member is arranged in the box body, a through hole is opened at the bottom of the box body, a lead-out member enters into the box body through the through hole, and is partially located above the transmission member;

[0006] A pair of welding assemblies are arranged on the upper surface of the transmission member, and the welding assemblies are used to fix the corresponding lead-out members on the transmission member; the welding assemblies include a first welding member and a second welding member arranged at intervals, the first welding member or the second welding member is a secondary welding member, and a connecting member is arranged on the upper surface of the secondary welding member.

[0007] Furthermore, the first welding part is a tin-lead welding part, and the second welding part is a tin-lead-bismuth welding part, or the first welding part is a tin-lead-bismuth welding part, and the second welding part is a tin-lead welding part.

[0008] Furthermore, the distance between the first welding part and the second welding part is not less than 0.5 cm.

[0009] Furthermore, the fusible component is rosin, and the melting point of rosin is 140°-160°.

[0010] Furthermore, the bismuth content in the tin-lead-bismuth solder is 20%-32%.

[0011] Furthermore, the lead-out member includes a first lead-out portion and a second lead-out portion, the first lead-out portion is inserted into the through hole, and the second lead-out portion is located above the transmission member;

[0012] When the first welding part is a secondary welding part, the position of the first lead-out part close to the second lead-out part is fixed to the first welding part by a connecting part, and the position away from the second lead-out part is welded and fixed by a second welding part;

[0013] When the second welding part is a secondary welding part, the position of the first lead-out part close to the second lead-out part is welded and fixed by the first welding part, and the position away from the second lead-out part is fixed to the second welding part by the connecting part.

[0014] Furthermore, the angle between the first lead-out portion and the second lead-out portion is 90°-110°.

[0015] Furthermore, a cover plate is provided above the transmission component, and the lead-out component and the diode are squeezed between the transmission component and the cover plate.

[0016] Furthermore, at least two pillars are respectively arranged on both sides of the transmission member at the bottom of the box body, mounting feet are arranged on both sides of the cover plate, mounting holes are opened on the mounting feet, and the cover plate is connected to the pillars through the mounting holes.

[0017] Furthermore, a box cover is provided at the top of the box body, and the space formed by the box body and the box cover is filled with silica gel.

[0018] Compared with the prior art, the beneficial effects of the utility model are:

[0019] (1) The photovoltaic junction box of the utility model includes a transmission member arranged in the box body, and a pair of welding assemblies are arranged on the upper surface of the transmission member, and the welding assembly includes a first welding member and a second welding member arranged at intervals, and the first welding member or the second welding member is a secondary welding member, and a connecting member is pasted on the upper surface of the secondary welding member; in one technical scheme, the second welding member is a secondary welding member, and when the lead-out member is led out from the through hole and contacts with the upper surface of the first welding member, a resistance welding head is used to heat and apply a certain pressure, and the heat is conducted to the first welding member through the lead-out member, and the first welding member melts and fully contacts with the lead-out member and wraps the lead-out member, wherein a part of the heat is conducted to the connecting member through the lead-out member, and the connecting member melts and bonds with the lead-out member, and when the lead-out member and the first welding member have a virtual connection or an internal welding defect, the high temperature generated at the welding point is conducted to the second welding member (i.e., the secondary welding member) through the lead-out member, so that the second welding member melts, thereby realizing secondary welding with the lead-out member.

[0020] (2) A cover plate is also provided above the transmission member of the utility model, and the lead-out member and the diode are squeezed between the transmission member and the cover plate. The cover plate can apply pressure to the lead-out member and the transmission member to prevent the two from being separated, and the heat generated by the large resistance of the welding defect can be discharged through the cover plate, thereby reducing the influence of the heat on the leakage of the diode and reducing the heat energy loss; and the part of the cover plate that contacts the diode can more evenly discharge the heat generated by the diode when it is working, thereby achieving the effect of cooling the diode and protecting the diode from being burned. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is an exploded structural diagram of a photovoltaic junction box in the utility model in which the first welding part is a low-temperature welding part;

[0023] Figure 2 This is an exploded structural diagram of the second welding part in the photovoltaic junction box of the utility model being a low-temperature welding part;

[0024] Figure 3 This is the assembly structure diagram of the transmission component and the lead-out component of the utility model;

[0025] Among them: 1-box body, 11-through hole, 2-box cover, 3-transmission member, 4-welding assembly, 41-first welding member, 42-second welding member, 43-connecting member, 5-lead-out member, 51-first lead-out part, 52-second lead-out part, 6-cover plate, 61-mounting foot, 62-mounting hole, 7-pillar. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the utility model.

[0027] The following is combined with Figure 1 To Attachment Figure 3 And specific embodiments describe the present invention in detail.

[0028] like Figure 1-3 As shown, the utility model provides a photovoltaic junction box, including a box body 1 and a box cover 2 arranged at the top of the box body 1; a transmission member 3 is arranged in the cavity of the box body 1, a through hole 11 is opened at the bottom of the box body 1, and a lead-out member 5 enters the box body 1 from the through hole 11 and extends to the top of the transmission member 3; a pair of welding assemblies 4 are arranged on the upper surface of the transmission member 3, and the welding assemblies 4 are used to fix the corresponding lead-out members 5 on the transmission member 3; the welding assembly 4 includes a first welding member 41 and a second welding member 42 arranged at intervals along the length direction of the transmission member 3, the first welding member 41 and the second welding member 42 are located at different positions of a single lead-out member 5, and it can also be understood that each lead-out member 5 has two fixed positions, and the first welding member 41 and the second welding member 42 are respectively fixed to the transmission member 3 at the two fixed positions.

[0029] In some embodiments, Figure 1 As shown, the first welding part 41 is a secondary welding part, and a connecting part 43 is provided on the upper surface of the first welding part 41. When the lead-out part located above the transmission part 3 contacts the upper surface of the second welding part 42, the resistance welding head is used to heat and apply a certain pressure thereto, and the heat is conducted to the second welding part 42 through the lead-out part 5, and the second welding part 42 melts and fully contacts and wraps the lead-out part 5, wherein a part of the heat is conducted to the connecting part 43 through the lead-out part 5, and the connecting part 43 melts and bonds with the lead-out part 5. When the lead-out part 5 and the transmission part 3 are in virtual contact or there are internal defects in the welding, a large amount of heat will be generated in the contact part due to the resistance thermal effect, forming a high temperature environment. At this time, the heat is conducted to the first welding part 41 (i.e., the secondary welding part) through the lead-out part 5, so that the first welding part 41 melts and wraps the lead-out part 5, thereby realizing secondary welding with the lead-out part 5.

[0030] In other embodiments, Figure 2As shown, the second welding part 42 is a secondary welding part, and a connecting part 43 is provided on the upper surface of the second welding part 42. After the lead-out part 5 located above the transmission part 3 contacts the upper surface of the first welding part 41, the resistance welding head is used to heat and apply a certain pressure, and the heat is transferred to the first welding part 41 through the lead-out part 5, and the first welding part 41 melts and fully contacts and wraps the lead-out part 5, wherein a part of the heat is transferred to the connecting part 43 through the lead-out part, and the connecting part 43 melts and bonds with the lead-out part 5. When the lead-out part 5 and the transmission part 3 are in virtual contact or there are internal defects in the welding, a large amount of heat will be generated in the contact part due to the resistance thermal effect, forming a high-temperature environment. At this time, the heat is transferred to the second welding part 42 (i.e., the secondary welding part) through the lead-out part 5, so that the second welding part 42 melts and wraps the lead-out part 5, and the secondary welding with the lead-out part 5 is realized.

[0031] In the present application, the welding temperature of the secondary welding part is not greater than 200° C., preferably 165° C.-200° C. When the temperature reaches the above temperature, the secondary welding part can be melted to achieve secondary welding of the lead-out part 5.

[0032] It should be noted that the connecting piece 43 in the above embodiment refers to the connecting piece 43 that can bond the lead-out piece 5 and the secondary welding piece together under the action of welding heat. The present application does not limit the specific material of the connecting piece 43, and those skilled in the art can choose according to the specific situation.

[0033] In some embodiments, the connecting member 3 is a fixing plate, and the lead-out member 5 is clamped between the fixing plate and the secondary welding member. The fixing plate fixes the lead-out member on the secondary welding member. It can be understood that when the lead-out member 5 is installed, the lead-out member 5 is fixed to the secondary welding member through the fixing plate, and then another welding member is welded after fixation; when the lead-out member 5 and the transmission member 3 are in virtual contact or there are internal defects in the welding, the contact part will generate a large amount of heat due to the resistance thermal effect, forming a high-temperature environment. At this time, the heat is conducted to the secondary welding member through the lead-out member 5, causing the secondary welding member to melt and wrap the lead-out member 5, thereby realizing secondary welding with the lead-out member 5.

[0034] The structure of the photovoltaic junction box of the present application can prevent the lead-out parts and transmission parts of the solar cell module from being falsely connected, and the contact position between the two parts generates a large amount of heat due to the resistance thermal effect, which leads to the risk of diode leakage, power loss, burning of solar cell modules, junction boxes, and even fire, thereby reducing the maintenance costs and property losses caused by them. At the same time, it can also reduce the power loss caused by the quality problems of the welding of the lead-out parts and transmission parts of the solar cell module, when they are separated outdoors, and the inability to extract the power.

[0035] In a preferred embodiment, the first welding part 41 is a tin-lead welding part, and the second welding part 42 is a tin-lead-bismuth welding part, or the first welding part 41 is a tin-lead-bismuth welding part, and the second welding part 42 is a tin-lead welding part, and the spacing between the first welding part 41 and the second welding part 42 is not less than 0.5 cm; wherein, the tin-lead welding part can be melted under the heating condition of the resistance welding head to fully contact and wrap the lead-out part 5, and the tin-lead-bismuth welding part can be melted in the high temperature environment generated by the virtual connection between the lead-out part 5 and the transmission part 3, and the lead-out part 5 and the tin-lead-bismuth welding part are re-welded.

[0036] Specifically, in some embodiments, the connector 43 is rosin, and the melting point of rosin ranges from 140° to 160°. When the lead-out member 5 is welded with the tin-lead solder, part of the heat is transmitted to the rosin through the lead-out member, and the rosin melts to bond the lead-out member 5 with the tin-lead-bismuth solder. When the lead-out member 5 and the tin-lead solder are in virtual contact, the high temperature generated at the welding point is conducted to the tin-lead-bismuth solder through the lead-out member 5, so that the tin-lead-bismuth solder melts and realizes the secondary welding with the lead-out member 5. It should be noted that the coverage range and coverage amount of rosin on the secondary welding part in this application are sufficient to make the rosin melt under the action of welding heat and fully bond with the lead-out member 5, and there is no gap between the rosin and the lead-out member 5, so as to prevent the subsequent photovoltaic junction box from penetrating through the gap between the lead-out member 5 and the rosin when the silicone is potted, affecting the welding of the tin-lead-bismuth solder and the lead-out member 5; at the same time, the rosin plays a role in assisting the welding when the tin-lead-bismuth solder and the lead-out member are welded.

[0037] Preferably, the bismuth content in the tin-lead-bismuth solder is 20%-32%. The tin-lead-bismuth solder within this range can achieve low-temperature welding.

[0038] The lead-out part 5 of the present application includes a first lead-out part 51 and a second lead-out part 52. The first lead-out part 51 is located on the surface of the transmission part 3 facing the box cover 2, and the second lead-out part 52 is inserted into the corresponding through hole 11. The angle between the first lead-out part 51 and the second lead-out part 52 is 90°-110°. After being bent, the first lead-out part 51 can be fixed to the first welding part 41 and the second welding part 42 in sequence, that is, the first welding part 41 and the second welding part 42 are located at different positions in the length direction of the first lead-out part 51.

[0039] Specifically: before the secondary welding, if the first welding part 41 is a secondary welding part, the position of the first lead-out part 51 close to the second lead-out part 52 is fixed to the first welding part 41 by the connecting part 43, and the position away from the second lead-out part 52 is welded and fixed by the second welding part 42; if the second welding part 42 is a secondary welding part, the position of the first lead-out part 51 close to the second lead-out part 52 is welded and fixed by the first welding part 41, and the position away from the second lead-out part 52 is fixed to the second welding part 42 by the connecting part 43.

[0040] Specifically, the lead-out member 5 in the present embodiment is a bus bar led out from a solar cell module. A solar cell module usually has three junction boxes, each of which has a bypass diode and two bus bars. Both bus bars need to be inserted into the box body 1. Correspondingly, there are also two through holes 11 at the bottom of the box body 1. The two bus bars are inserted from the bottom through holes 11, extend to the top of the transmission member 3, and then bend in opposite directions. The two bus bars are respectively welded and fixed to two welding assemblies 4; the first welding member 41 is close to the second lead-out portion 52, and the second welding member 42 is far away from the second lead-out portion 52.

[0041] Specifically, a cover plate 6 is further provided above the transmission member 3, and the lead-out member 5 and the diode are squeezed between the transmission member 3 and the cover plate 6. The cover plate 6 can apply pressure to the lead-out member 5 and the transmission member 3 to prevent the two from detaching. Preferably, the cover plate 6 is a metal cover plate with a heat conduction function, which can conduct the heat generated by the large resistance of the welding defect through the cover plate 6, thereby reducing the influence of the heat on the diode leakage and reducing the heat energy loss. And the part of the cover plate 6 that contacts the diode can conduct the heat generated by the diode when it is working more evenly, realize the effect of cooling the diode, and thus protect the diode from being burned. The present application does not limit the specific shape and quantity of the cover plate 6, and the cover plate 6 can be designed to be split, that is, as shown in the attached Figure 1 There are two middle cover plates 6, and the two cover plates 6 are respectively arranged corresponding to the lead-out member 5. The cover plates 6 can realize the functions of fixing the lead-out member 5 and the transmission member 3 and heat conduction, which all belong to the protection scope of this application.

[0042] Specifically, at least two pillars 7 are respectively arranged on both sides of the transmission member 3 at the bottom of the box body 1, and mounting feet 61 are arranged on both sides of the cover plate 6. The mounting feet 61 are provided with mounting holes 62. When the cover plate 6 is connected to the pillars 7 through the mounting holes 62, a pressure is applied to the pillars 7 to partially deform the pillars, thereby fixing the cover plate 6. Preferably, the pillars 7 are plastic pillars, which are easy to deform and can easily fix the cover plate 6 in the box body 1.

[0043] Specifically, the transmission component 3 is a metal transmission component, and is a rectangular metal plate. The rectangular metal plate matches the inner cavity of the box body 1, and the rectangular metal plate is provided with mounting holes corresponding to the pillars. During installation, the rectangular metal plate is first installed on the pillar 7, and then the corresponding lead-out parts, welding components, etc. are installed, and finally the cover plate 6 is installed on the pillar 7.

[0044] Specifically, an adhesive layer is provided on the bottom surface of the outer side of the box body 1 for adhering the photovoltaic junction box to the solar cell assembly.

[0045] Specifically, the space formed by the box body 1 and the box cover 2 is filled with organic silica gel, and the organic silica gel completely wraps the transmission component 3 and the cover plate 6 in the box body 1 .

[0046] The installation process of the battery box and the busbar of the photovoltaic module in this application is as follows:

[0047] Step 1: A through hole 11 is opened at the bottom of the box body 1 of the photovoltaic junction box, and the bottom of the outer side of the box body 1 is coated with organic silicone. The bus bar led out from the solar cell module is passed through the through hole, and then the box body 1 of the photovoltaic junction box is pressed to make it adhere to the solar cell module.

[0048] Step 2: Bend the bus bar 90°-110° toward the tin-lead solder attached to the transmission component 3 in the photovoltaic junction box, and press it sufficiently to make it fit tightly with the rosin adhered to the tin-lead solder and the tin-lead-bismuth solder.

[0049] Step 3: Use a resistance welding head to heat and apply a certain pressure on the busbar surface above the tin-lead solder. The heat is transferred to the tin-lead solder through the busbar, and the tin-lead solder melts and fully contacts and wraps the busbar, thereby achieving welding. Part of the heat is transferred to the rosin attached to the tin-lead-bismuth solder through the busbar, and the rosin melts and bonds to the busbar.

[0050] Step 4: The bottom of the photovoltaic junction box body 1 is designed with a support 7 for fixing the cover plate 6. Align the mounting hole 62 of the cover plate 6 with the support 7 and press it down to make the cover plate 6 fully contact with the packaging material of the bus bar and the diode. Apply pressure to the support 7 to cause it to partially deform, thereby fixing the cover plate 6.

[0051] Step 5: Fill the box body 1 of the photovoltaic junction box with organic silicone specially used for the photovoltaic junction box. The organic silicone is required to completely wrap the transmission component 3 and the cover plate 6 in the box body.

[0052] Step 6: Cover the box cover 2 of the photovoltaic junction box on the box body 1 by pressing.

[0053] The utility model is further described above with the help of specific embodiments, but it should be understood that the specific description here should not be construed as limiting the essence and scope of the utility model. Various modifications made to the above embodiments by ordinary technicians in this field after reading this specification are all within the scope of protection of the utility model.

Claims

1. A photovoltaic junction box, characterized in that: It comprises a box body; a transmission member is arranged in the box body, a through hole is opened at the bottom of the box body, and the lead-out member enters into the box body through the through hole and is partially located above the transmission member; A pair of welding assemblies are arranged on the upper surface of the transmission member, and the welding assemblies are used to fix the corresponding lead-out members on the transmission member; the welding assemblies include a first welding member and a second welding member arranged at intervals, and the first welding member or the second welding member is a secondary welding member, and a connecting member is arranged on the upper surface of the secondary welding member.

2. The photovoltaic junction box according to claim 1, characterized in that: The first welding part is a tin-lead welding part, and the second welding part is a tin-lead-bismuth welding part; or the first welding part is a tin-lead-bismuth welding part, and the second welding part is a tin-lead welding part.

3. The photovoltaic junction box according to claim 2, characterized in that: The distance between the first welding part and the second welding part is not less than 0.5 cm.

4. The photovoltaic junction box according to claim 2, characterized in that: The bismuth content in the tin-lead-bismuth solder piece is 20%-32%.

5. The photovoltaic junction box according to claim 1, characterized in that: The connecting piece is rosin.

6. The photovoltaic junction box according to claim 1, characterized in that: The lead-out member includes a first lead-out portion and a second lead-out portion, the first lead-out portion is inserted into the through hole, and the second lead-out portion is located above the transmission member; When the first welding part is a secondary welding part, the position of the first lead-out part close to the second lead-out part is fixed to the first welding part by the connecting part, and the position away from the second lead-out part is fixed by welding by the second welding part; When the second welding part is a secondary welding part, the first lead-out part is welded and fixed at a position close to the second lead-out part by the first welding part, and is fixed to the second welding part at a position away from the second lead-out part by the connecting part.

7. The photovoltaic junction box according to claim 6, characterized in that: The included angle between the first lead-out portion and the second lead-out portion is 90°-110°.

8. The photovoltaic junction box according to any one of claims 1 to 7, characterized in that: A cover plate is also arranged above the transmission member, and the lead-out member and the diode are squeezed between the transmission member and the cover plate.

9. The photovoltaic junction box according to claim 8, characterized in that: The bottom of the box body is located on both sides of the transmission member and is respectively provided with at least two pillars, and the cover plate is provided with mounting feet on both sides. The mounting feet are provided with mounting holes, and the cover plate is connected to the pillars through the mounting holes.

10. The photovoltaic junction box according to claim 1, characterized in that: A box cover is also arranged on the top of the box body, and silica gel is filled in the space formed by the box body and the box cover.

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