Photovoltaic module welding method

Abstract

A welding strip comprises a conductive strip, a conductive welding layer and an insulating layer, the conductive welding layer is arranged on at least one side, facing a battery piece, of the conductive strip, the insulating layer is arranged on at least one side, deviating from the conductive strip, of the conductive welding layer facing the battery piece, and the insulating layer is provided with a first area and a second area. The welding method comprises the steps that a first area is irradiated through laser, an insulating material of the first area absorbs laser energy and then is decomposed and gasified, so that the first area is removed, a conductive welding layer covered by the first area is exposed, and a second area is reserved; arranging a welding strip on the battery piece, wherein the conductive welding layer exposed after the first region is removed is positioned above a welding spot of the battery piece; and spot welding is conducted on the position where the welding spot is located, so that the conductive welding layer above the welding spot is melted and welded to the welding spot. The welding effect is good, the welding strip and the battery piece are separated through the second area, short circuit of the battery piece after welding can be effectively prevented, and cost is low.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic module manufacturing technology, specifically, it relates to a photovoltaic module welding method. Background Technology

[0002] A solar cell mainly consists of a substrate, a semiconductor layer, a passivation layer, and an electrode layer. The substrate is made of silicon wafers with different conductivity types. The electrode layer needs to be connected to the semiconductor layer to draw out the current, and then multiple cells are connected to form a photovoltaic module by soldering ribbons.

[0003] Typically, the entire surface of the solder ribbon is covered with solder for contacting and soldering the grid lines on the solar cell. However, when soldering the solder ribbon to the grid lines on the solar cell, the solder in the non-soldering areas of the solder ribbon melts and flows when heated, causing the solder in the non-soldering areas of the solder ribbon to solder to the wrong areas on the solar cell, resulting in incorrect conductive connections of the solder ribbon.

[0004] To avoid the above problems, existing technology prints insulating adhesive in the vicinity of the welding area of ​​the battery cell according to the positive and negative electrodes. This method has a simple process and is relatively mature, but it is costly. After the insulating adhesive is printed, there is a height difference between the solder strip and the welding point area on the battery cell, which affects the welding.

[0005] The patent, CN202310357748.6, entitled "A Welding Method and a Photovoltaic Module," discloses that an insulating layer covers the entire outer surface of a conductive welding layer. Spot welding is performed on the welding points corresponding to the welding strips, causing the conductive welding layer to melt at the corresponding welding points. This also causes the insulating layer to be damaged at the corresponding welding points, forming an exposed area. The molten conductive welding layer then contacts and welds with the welding points of the workpiece through the exposed area.

[0006] This method does not pre-peel the solder strip to the corresponding solder joint; instead, it directly melts the insulation layer during the soldering process, allowing the molten conductive solder layer to contact and weld with the solder joint. This results in issues such as the molten insulation layer sticking to the solder joint, slagging of the insulation layer after soldering, a small contact area between the solder strip and the solder joint, poor soldering effect, low soldering pull force, and the presence of partial insulation layer on the solder joint surface, leading to poor conductivity. Summary of the Invention

[0007] In view of this, this application provides a photovoltaic module welding method, which uses laser to decompose the insulating layer on the vaporized welding strip in the area corresponding to the welding point to expose the conductive welding layer in that area, and then melts the exposed conductive welding layer to weld it together with the welding point. The welding effect is good, and the photovoltaic module will not experience short circuit after welding.

[0008] A photovoltaic module welding method includes a welding strip comprising a conductive strip, a conductive welding layer, and an insulating layer. The conductive welding layer is provided on at least the side of the conductive strip facing the solar cell, and an insulating layer is provided on at least the side of the conductive welding layer facing the solar cell away from the conductive strip. The insulating layer has a first region and a second region. The welding method includes:

[0009] S1: By irradiating the first area with a laser, the insulating material in the first area absorbs the laser energy and decomposes and vaporizes, thereby removing the first area and exposing the conductive welding layer covered by the first area, while retaining the second area.

[0010] S2: Arrange the solder ribbons on the battery cell, and the conductive solder layer exposed after removing the first area is located above the solder joint of the battery cell;

[0011] S3: Spot weld the location of the weld point so that the conductive welding layer above the weld point melts and welds together with the weld point.

[0012] Preferably, in step S1, the laser pulse width is 60–200 ns, the laser frequency is 40–200 kHz, the laser power is 40–100 W, the scanning speed is 4000–6000 mm / s, and the scanning time for a single area is 80–100 ms.

[0013] Preferably, in step S3, the spot welding method is to irradiate the location of the weld point with a laser, the laser power is 40-80W, and the scanning time is 200-600ms.

[0014] Preferably, the thickness of the insulating layer is 10–35 μm.

[0015] Preferably, the insulating layer is made of one or more materials selected from epoxy resin insulating varnish, PFA black raw material, polytetrafluoroethylene, and silicone.

[0016] Preferably, after step S1 and before step S2, the exposed conductive solder layer is cleaned.

[0017] Preferably, the exposed conductive solder layer is ultrasonically cleaned, and the cleaning agent for ultrasonic cleaning includes any one or more of dibutyl phthalate, ethyl acetate, acetone, cyclohexanone, and toluene.

[0018] Preferably, in step S1, the energy density of the laser is greater than the damage threshold of the first region but less than the damage threshold of the conductive welding layer.

[0019] Preferably, the melting point of the insulating layer is greater than the melting point of the conductive solder layer, and the melting point of the conductive solder layer is less than the melting point of the conductive strip, and / or,

[0020] The thickness of the first region is less than the thickness of the second region.

[0021] Preferably, the solder strip is soaked in flux before step S2.

[0022] Preferably, the welding temperature in step S3 is 200–400°C; and / or,

[0023] The conductive strip is made of one or more of copper, nickel, aluminum, and silver; and / or,

[0024] The conductive welding layer is made of one or more of the following materials: nickel, tin, bismuth, silver, copper, aluminum, titanium, lead, indium, and gallium.

[0025] The beneficial effects of this application are: by irradiating the first area of ​​the insulating layer with a laser, the insulating material in the first area can be effectively removed, exposing the conductive welding layer covered by the first area, thus avoiding the insulating material in the first area from affecting the welding effect. Then, spot welding is performed at the location of the welding point, so that the exposed conductive welding layer melts and welds together with the welding point on the battery cell. It has a large welding contact area, and the welding effect is good. Moreover, the welding strip and the battery cell are separated by the second area, which can effectively prevent the battery cell from short-circuiting after welding. It has a low cost and a large welding pull force. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0028] Figure 1 This is a schematic diagram of the structure of the welding strip provided in this application;

[0029] Figure 2 The scanning path of the laser when irradiating the first region as provided in this application;

[0030] Figure 3 This is a schematic diagram of the structure where the solder ribbons are arranged on the solar cell.

[0031] In the diagram: 1-Solder strip; 11-Conductive strip; 12-Conductive welding layer; 13-Insulating layer; 131-First region; 132-Second region; 2-Laser lift-off area; 3-Battery cell; 4-Solder joint. Detailed Implementation

[0032] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0033] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] According to its shape, the welding strip 1 can be divided into various types such as round welding strip and flat welding strip. The welding strip 1 generally includes a conductive strip 11 and a conductive welding layer 12. For flat welding strip, at least one conductive welding layer 12 is provided on the side of the conductive strip 11 facing the battery cell. More preferably, regardless of the type of welding strip 1, a conductive welding layer 12 is wrapped around the outside of the conductive strip 11.

[0035] In this application, flat welding tape is preferably used for welding photovoltaic modules, such as... Figure 1 As shown, the conductive welding layer 12 of the solder strip 1, at least facing the battery cell 3, has an insulating layer 13 on the side facing away from the conductive strip 11. This insulating layer 13 has a first region 131 and a second region 132. Of course, this application can also cover the outside of the conductive strip 11 with a conductive welding layer 12, so that the conductive strip 11 is covered with the conductive welding layer 12 on both the side facing the battery cell 3 and the side facing away from the battery cell 3. Then, an insulating layer 13 is covered on the conductive welding layer 12 facing the battery cell 3. This insulating layer 13 has a first region 131 and a second region 132. Alternatively, an insulating layer 13 can be covered on both the conductive welding layer 12 facing the battery cell 3 and the side facing away from the battery cell 3, that is, an insulating layer 13 is wrapped around the conductive welding layer 12.

[0036] The conductive strip 11 is made of one or more of copper, nickel, aluminum, and silver, and mainly serves to conduct electricity. Of course, this application is not limited to the above materials, and it can also be made of other conductive metal materials.

[0037] The conductive solder layer 12 is made of one or more of the following materials: nickel, tin, bismuth, silver, copper, aluminum, titanium, lead, indium, and gallium. Its primary purpose is to melt it and solder the solder ribbon 1 to the solder joint 4 on the solar cell 3. Alternatively, it can be any other metallic material that, upon melting, can solder the solder ribbon 1 to the solder joint 4, thus enabling the main grid lines of the solar cell 3 to conduct electricity with the solder ribbon 1.

[0038] The insulating layer 13 is made of one or more materials selected from epoxy resin insulating varnish, PFA black raw material, polytetrafluoroethylene, and silicone. It is mainly used to separate the solder ribbon 1 from the battery cell 3 and prevent the area outside the solder point 4 on the battery cell 3 from being welded to the solder ribbon 1, which would cause a short circuit in the battery cell 3.

[0039] refer to Figure 1-3 This embodiment provides a photovoltaic module welding method, which includes the following steps:

[0040] S1: By irradiating the first region 131 with a laser, the insulating material of the first region 131 absorbs the laser energy and decomposes and vaporizes, thereby removing the first region 131 and exposing the conductive welding layer 12 covered by the first region 131, while retaining the second region 132.

[0041] S2: The solder ribbon 1 is arranged on the battery cell 3, and the conductive solder layer 12 exposed after removing the first region 131 (i.e. the conductive solder layer 12 corresponding to the first region 131) is located above the solder joint 4 of the battery cell 3.

[0042] S3: Spot weld the location of the solder point 4 so that the conductive welding layer 12 above the solder point 4 melts and welds together with the solder point 4.

[0043] In this embodiment, laser irradiation is used to remove the insulating material of the first region 131. The high energy density laser peels off the first region 131. After absorbing the laser energy, the insulating material of the first region 131 decomposes, vaporizes, and even volatilizes, thus exposing the conductive welding layer 12 covered by the first region 131.

[0044] Specifically, this embodiment utilizes the high energy density of lasers to disrupt the adhesion between the insulating material of the first region 131 and the conductive welding layer 12 through thermal vibration and thermal shock mechanisms, causing the first region 131 to peel off from the surface of the conductive welding layer 12. During this process, the laser energy is absorbed by the insulating material of the first region 131, generating high temperatures that cause the insulating material to instantly heat up, burn, and vaporize. Simultaneously, the shock wave and acoustic shattering effect generated by the laser also aid in the peeling of the first region 131 from the surface of the conductive welding layer 12.

[0045] Because the laser action time on the first region 131 is very short, thermal damage to the conductive welding layer 12 covering the first region 131 can be avoided. Preferably, a pulsed laser is used to peel off the first region 131. The pulse of the pulsed laser is short, usually a single pulse time of nanosecond or less. When the insulating material absorbs the high-energy short-pulse laser energy, the temperature exceeds its ignition point on a nanosecond time scale, causing it to burn and vaporize.

[0046] In this embodiment, by controlling the laser energy density, the conductive welding layer 12 is not damaged during the laser stripping of the first region 131. Specifically, the laser pulse width for stripping the first region 131 is 60–200 ns, the laser frequency is 40–200 kHz, the laser power is 40–100 W, the scanning speed is 4000–6000 mm / s, and the scanning time for a single region is 80–100 ms. Within the above laser parameter range, the insulating material of the first region 131 can be effectively stripped without damaging the conductive welding layer 12 covering the first region 131, and there is no situation where laser heat conduction strips the second region 132.

[0047] Table 1 shows a comparison of the results of stripping the first region under different laser parameters.

[0048] Table 1. Stripping of the first region under different laser parameters.

[0049]

[0050] The residual insulation material ratio in Table 1 refers to the ratio of the residual insulation material in the first region 131 after laser stripping to the total insulation material in the first region 131. The change in the thickness of the conductive welding layer after stripping refers to the difference in the thickness of the conductive welding layer 12 corresponding to the first region 131 after stripping compared to the thickness of the conductive welding layer 12 before stripping.

[0051] As can be seen from Table 1, the laser parameters numbered 1 to 4 are all within the range of laser parameters provided in this embodiment, while the laser parameters numbered 5 to 6 are outside the range of laser parameters provided in this embodiment. When the values ​​of each laser parameter are within the range of laser parameters provided in this application, the first region 131 is peeled off, resulting in less residual insulating material in the first region 131 after peeling, which has little impact on subsequent welding. Furthermore, there is no over-peeling that would cause the conductive welding layer 12 corresponding to the first region 131 to be peeled off, nor would it damage the second region 132. In contrast, if the laser parameters are not within the range of laser parameters provided in this embodiment, there may be excessive residual insulating material in the first region 131 after peeling, affecting welding, or the conductive welding layer 12 corresponding to the first region 131 may also be peeled off during the peeling process, causing damage to the second region 132 adjacent to the first region 131.

[0052] Preferably, the energy density of the laser is greater than the damage threshold of the first region 131 and less than the damage threshold of the conductive welding layer 12.

[0053] High concentration of laser energy can cause localized deformation or even complete damage to the interior or surface of a material. The maximum laser power that a material can withstand per unit area is called its laser damage threshold, i.e., the minimum energy density at which the material is damaged. In this embodiment, the insulating layer 13 is mainly composed of hydrocarbon organic compounds, while the conductive solder layer 12 is typically made of tin-lead. This results in a different laser damage threshold between the conductive solder layer 12 and the insulating layer 13. By controlling the laser energy density to be greater than the damage threshold of the first region 131 but less than the damage threshold of the conductive solder layer 12, the insulating layer 13 can be removed without damaging the conductive solder layer 12.

[0054] like Figure 2 As shown, in step S1, when the laser scans the first region 131, each first region 131 has a laser stripping area 2, and the laser travels along the laser stripping area 2. Figure 2 The lines in the laser stripping area 2 shown are scanned to remove the first region 131. The single region scanning time in this embodiment refers to the time it takes for the laser to scan one first region 131 along the lines in the laser stripping area 2.

[0055] After the laser stripping of the first region 131, there may still be insulating material remaining in the first region 131. This residual insulating material will hinder the conductive welding layer 12 from melting and welding with the solder joint 4 during the laser welding process in step S3, resulting in a smaller welding contact area, affecting the welding effect, and thus affecting the performance of the final photovoltaic module.

[0056] Therefore, in this embodiment, after laser stripping of the first region 131, the exposed conductive solder layer is cleaned. Preferably, the residual insulating material in the first region 131 is removed by ultrasonic cleaning. The cleaning agent for ultrasonic cleaning may include any one or more of dibutyl phthalate, ethyl acetate, acetone, cyclohexanone, and toluene.

[0057] Of course, other methods can also be used to remove the residual insulating material in the first region 131, such as selecting sandpaper of appropriate grit to polish the residual insulating material in the first region 131. This application does not limit this.

[0058] Understandably, reference Figure 3Each solder ribbon 1 has an insulating layer 13 with multiple first regions 131 and second regions 132. The first regions 131 and second regions 132 are staggered. The number of first regions 131 on the solder point 1 is the same as the number of solder points 4 on the cell 3. When the solder ribbon 1 is arranged on the cell 3, each first region 131 is corresponding to a solder point 4. The conductive welding layer 12 exposed by peeling off the first region 131 is located above the corresponding solder point 4. Then, spot welding is performed on the location of the solder point 4 to melt the exposed conductive welding layer 12 and weld the solder point 4 to the solder ribbon 1. This process continues until all the solder points 4 on all the cells 3 in the photovoltaic module are welded to the solder ribbon 1 above them. The solder ribbon 1 is separated from the areas on the cell 3 other than the solder point 4 by the second region 132 to prevent short circuits caused by welding the areas on the cell 3 other than the solder point 4 to the solder ribbon 1.

[0059] Furthermore, in this embodiment, the spot welding method at the location of the solder joint is to irradiate the location of the solder joint 4 with a laser so that the conductive welding layer 12 melts and welds together with the solder joint 4. The laser power of the laser welding is 40-80W, the scanning time is 200-600ms, and the welding temperature is 200-400℃. Under this parameter range, the conductive welding layer 12 exposed by peeling off the first region 131 can melt, so that the solder strip 1 and the solder joint 4 are welded together, and the second region 132 will not be peeled, wrinkled, cracked, or detached, thus ensuring the insulation effect of the second region 132 and having high welding pull force.

[0060] Of course, spot welding at the location of weld point 4 can also be performed by high-temperature welding head spot welding or lamination welding, etc., and this application does not limit this.

[0061] In some embodiments, after laser stripping of the first region 131 and removal of the residual insulating material in the first region 131, the solder ribbon 1 can be immersed in flux for a certain period of time to coat the surface of the solder ribbon 1 with flux. Then, the solder ribbon 1 is arranged on the solar cell 3 for laser welding. The coating of flux can improve the welding effect between the solder ribbon 1 and the solder joint 4, thereby improving the electrical performance of the manufactured photovoltaic module.

[0062] In this embodiment, the melting point of the insulating layer 13 is greater than that of the conductive welding layer 12, while the melting point of the conductive welding layer 12 is less than that of the conductive strip 11. During laser welding, the temperature is controlled to reach the melting point of the conductive welding layer 12 by controlling the laser parameters. At this point, only the conductive welding layer 12 melts, while the second region 132, because its melting point is greater than that of the conductive welding layer 12, will not wrinkle or fall off due to receiving heat conducted by the laser, thus not affecting the insulation effect of the second region 132. Furthermore, the fact that the melting point of the conductive welding layer 12 is less than that of the conductive strip 11 allows the conductive welding layer 12 to melt without causing the conductive strip 11 to melt.

[0063] In some embodiments, the thickness of the insulating layer 13 is 10 to 35 μm. Within this range, the insulating material of the first region 131 can be effectively removed by laser, and the insulation performance of the second region 132 can be guaranteed, ensuring that the region other than the solder joint 4 on the battery cell 3 will not be connected to the solder strip 1 for conduction.

[0064] In other embodiments, the thickness of the first region 131 may be less than the thickness of the second region 132, so that the first region 131 can be removed more quickly.

[0065] Alternatively, the insulation material of the first region 131 can be different from that of the second region 132. For example, the insulation material of the first region 131 can be made of a material that is not heat-resistant and is easy to remove, while the insulation material of the second region 132 can be made of a heat-resistant material, so that the second region 132 can be removed in a better way without damaging the first region 131.

[0066] Preferably, the thickness of the conductive welding layer 12 is 15 to 40 μm. Within this range, the conductive welding layer 12 can form a good contact after melting and welding together with the welding point 4.

[0067] More preferably, the size of the first region 131 is the same as the size of the solder joint 4, so that the conductive welding layer 12 has a larger welding contact area with the solder joint 4 after melting, thereby improving the welding effect.

[0068] In this embodiment, during welding, only the conductive welding layer 12 corresponding to the first region 131 of the solder ribbon 1 melts and welds to the solder joint 4, while the non-welding areas are insulated by the second region 132. This prevents short circuits caused by solder ribbon 1 shifting or the conductive welding layer 12 melting and flowing during welding, which could result in short circuits between the solder ribbon 1 and the non-welding areas of the solar cell 3. The welding effect is good, short circuits are not observed, and the resulting photovoltaic module has excellent electrical performance at a lower cost.

[0069] Furthermore, before welding, the first region 131 is decomposed and vaporized by laser, which can effectively peel the first region 131 off from the conductive welding layer 12 without damaging the conductive welding layer 12 and the second region 132. The residual insulating material in the first region 131 is cleaned by ultrasonic cleaning and other methods, so that there is a large welding contact area between the welding strip 1 and the welding point 4, ensuring that the exposed conductive welding layer 12 can form a tight contact with the welding point 4 after melting, thereby achieving a good conductivity effect.

[0070] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on its differences from other embodiments, and similar or identical parts between embodiments can be referred to interchangeably. For the apparatuses disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0071] It should be noted that, in the description of this application, the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component centrally located at the same time.

[0072] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0073] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photovoltaic module welding method, wherein the welding strip comprises a conductive strip, a conductive welding layer, and an insulating layer, wherein at least the conductive strip has a conductive welding layer on the side facing the solar cell, and at least the conductive welding layer facing the solar cell has an insulating layer on the side facing away from the conductive strip, wherein the insulating layer has a first region and a second region, characterized in that, The welding method includes: S1: By irradiating the first area with a laser, the insulating material in the first area absorbs the laser energy and decomposes and vaporizes, thereby removing the first area and exposing the conductive welding layer covered by the first area, while retaining the second area. S2: Arrange the solder ribbons on the battery cell, and the conductive solder layer exposed after removing the first area is located above the solder joint of the battery cell; S3: Spot weld the location of the weld point so that the conductive welding layer above the weld point melts and welds together with the weld point.

2. The photovoltaic module welding method according to claim 1, characterized in that, In step S1, the laser pulse width is 60–200 ns, the laser frequency is 40–200 kHz, the laser power is 40–100 W, the scanning speed is 4000–6000 mm / s, and the scanning time for a single region is 80–100 ms.

3. The photovoltaic module welding method according to claim 1, characterized in that, In step S3, the spot welding method is to irradiate the location of the weld point with a laser, the laser power is 40-80W, and the scanning time is 200-600ms.

4. The photovoltaic module welding method according to claim 1, characterized in that, The thickness of the insulating layer is 10–35 μm.

5. A photovoltaic module welding method according to claim 1, characterized in that, The insulating layer is made of one or more materials selected from epoxy resin insulating varnish, PFA black raw material, polytetrafluoroethylene, and silicone.

6. A photovoltaic module welding method according to claim 1, characterized in that, After step S1 and before step S2, the exposed conductive solder layer is cleaned.

7. A photovoltaic module welding method according to claim 6, characterized in that, The exposed conductive solder layer is ultrasonically cleaned using an ultrasonic cleaning agent including any one or more of dibutyl phthalate, ethyl acetate, acetone, cyclohexanone, and toluene.

8. A photovoltaic module welding method according to any one of claims 1-7, characterized in that, In step S1, the energy density of the laser is greater than the damage threshold of the first region but less than the damage threshold of the conductive welding layer.

9. A photovoltaic module welding method according to any one of claims 1-7, characterized in that, The melting point of the insulating layer is greater than that of the conductive solder layer, and the melting point of the conductive solder layer is less than that of the conductive strip, and / or, The thickness of the first region is less than the thickness of the second region.

10. A photovoltaic module welding method according to any one of claims 1-7, characterized in that, Before proceeding to step S2, the solder strip is soaked in flux.

11. A photovoltaic module welding method according to any one of claims 1-7, characterized in that, The welding temperature in step S3 is 200–400℃; and / or, The conductive strip is made of one or more of copper, nickel, aluminum, and silver; and / or, The conductive welding layer is made of one or more of the following materials: nickel, tin, bismuth, silver, copper, aluminum, titanium, lead, indium, and gallium.

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