Method for inspecting a solar cell substrate and an inspection apparatus therefor

Abstract

The application discloses a solar cell substrate inspection method and device, and belongs to the field of photovoltaic cells. The first area of the solar cell substrate is contacted with the inspection liquid uniformly. Under the action of the inspection liquid, the copper metal in the first area which is not covered by the residual glue can react with the inspection liquid, and presents a second color which is different from the first color of the copper metal. Therefore, whether the residual glue exists can be judged by observing the color of the first area. By observing the color of the first area after the treatment of the inspection liquid, whether the residual glue exists in the first area can be judged quickly, and the inspection process can not rely on complex and expensive inspection equipment, and the operation is simple.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cell technology, and more specifically, to a method and apparatus for testing solar cell substrates. Background Technology

[0002] Currently, one of the cutting-edge solar photovoltaic technologies is the use of copper interconnect technology to replace traditional silver paste printing. Besides cost, another major advantage of copper interconnect technology over traditional silver paste printing is its ability to produce fine lines. One of the core technologies for achieving fine lines is the pattern transfer technology of wet-film photosensitive emulsion. Copper interconnect battery technology uses wet-film photosensitive emulsion printing, developing, and electroplating to create the copper grid lines of the battery cells, replacing traditional silver paste printing technology.

[0003] However, this technology, which uses wet-film photosensitive emulsion, results in a certain proportion of residual emulsion after development, leading to incomplete development. Unlike traditional industries, this photosensitive emulsion is a colorless and transparent organic polymer material, making residual emulsion undetectable during development. Incomplete development due to residual emulsion can cause grid breakage defects, thus causing significant problems in actual production. Summary of the Invention

[0004] The purpose of this application is to provide a method and apparatus for inspecting solar cell substrates, so as to partially or completely improve the inspection problem of incomplete development of solar cell substrates in related technologies.

[0005] In a first aspect, embodiments of this application provide a method for inspecting a solar cell substrate. The solar cell substrate includes a copper seed layer and a photosensitive adhesive layer stacked together. A portion of the solar cell substrate is treated to remove the photosensitive adhesive layer, forming a first region. The inspection method is used to inspect whether transparent residual adhesive exists in the first region. The inspection method includes:

[0006] The test solution is applied to the first area, and the color of the first area is observed. The test solution contains a substance that can react with copper and change the color of copper to a second color. Before the test solution is applied to the first area, the first area is the first color. The presence of residual adhesive in the first area is determined by whether the color of the first area has completely changed: if the first area retains the first color, it indicates that there is residual adhesive in the first area.

[0007] After a portion of the photoresist layer is removed from a solar cell substrate, residual photoresist may remain in the first area. This residual photoresist adheres to the surface of a portion of the copper seed layer, preventing that portion from being exposed in the first area. Because the residual photoresist is transparent, even when it covers the first area, the observed color of the first area remains the color of the copper seed layer, i.e., the first color. In the above implementation, a testing solution is used to uniformly contact the first area. This allows the copper metal not covered by residual photoresist in the first area formed after the photoresist layer removal to directly contact the testing solution and react chemically, exhibiting a second color different from the first color of the copper metal. Therefore, the presence of residual photoresist can be determined by observing the color of the first area.

[0008] That is, if the first area still retains the first color after treatment with the test solution, it means that the part that retains the first color has not reacted with the test solution, thus indicating that there is residual adhesive covering the location where the first color is retained.

[0009] In conjunction with the first aspect, in an optional embodiment of this application, the first region is used for electroplating thickening to form electroplated copper grid lines.

[0010] In the fabrication of solar cell substrates, a photosensitive adhesive layer needs to be coated onto a copper seed layer. Then, part of the photosensitive adhesive layer is removed, forming a first region of exposed copper on the surface of the solar cell substrate. This facilitates the subsequent electroplating of copper grid lines on this first region. During this process, an inspection solution is used to examine the first region used for electroplating the copper grid lines. This allows for timely detection of any residual adhesive in the first region, thereby reducing the likelihood of grid line defects during the subsequent electroplating process.

[0011] In conjunction with the first aspect, in an optional embodiment of this application, if the entire color of the first region is the second color, it indicates that the first region has no residual adhesive; if the entire color of the first region is the first color, it indicates that the first region is fully covered with residual adhesive; if the color of the first region includes both the first and second colors, it indicates that the first region is partially covered with residual adhesive.

[0012] If there is no residual adhesive in the first area, after the testing solution covers the first area, the testing solution will react with the copper in the first area, causing the copper in the first area to change to the second color. At this time, the observed color of the first area will be entirely the second color.

[0013] If the first region is completely covered with a layer of residual adhesive, then after the test solution covers the first region, the test solution cannot change the color of the first region to the second color. In this case, the observed color of the first region will still be the first color.

[0014] If a portion of the first region is covered with residual adhesive, after the testing solution covers the first region, the solution will only cause the copper in the uncovered areas of the first region to change to the second color, while the areas covered with residual adhesive will retain the first color. In this case, the observed color of the first region will be both the first and second colors.

[0015] In conjunction with the first aspect, in an optional embodiment of this application, the test solution includes stannous salt and copper ion complexing agent, and the pH of the test solution is not greater than 1;

[0016] Optionally, the copper ion complexing agent is selected from at least one of thiourea and citric acid.

[0017] Using a testing solution to detect the presence of residual adhesive in the first area can prevent grid breakage during subsequent copper plating for grid fabrication. Furthermore, when the testing solution provided in this example, comprising stannous salt and a copper ion complexing agent, with a pH not exceeding 1, is uniformly applied to the first area, the stannous ions of the stannous salt in the testing solution, under a strongly acidic environment and with the action of the copper ion complexing agent, can undergo a displacement reaction with the copper in the first area not covered by residual adhesive. This causes metallic tin to precipitate on the surface of the copper layer in that area, exhibiting a milky white secondary color characteristic of metallic tin.

[0018] By observing whether the color of the first area after treatment with the test solution provided in this example appears as a second color different from the first color, it can be determined whether there is residual adhesive in the first area.

[0019] In conjunction with the first aspect, in an optional embodiment of this application, the copper ion complexing agent is thiourea, and the stannous salt is (CH3SO3)2Sn.

[0020] Adding thiourea or citric acid can react with Cu 2+ Cu + Stable complex ions are formed. For example, the addition of thiourea, under strongly acidic conditions, can form [Cu(NH₂CSNH₂)₄]. 2+ [Cu(NH2CSNH2)4] + Copper ion complexing agent. Adding a copper ion complexing agent to the test solution can adjust the electrode potential, making Sn... 2+ It can undergo a displacement reaction with the Cu it comes into contact with, precipitating metallic tin.

[0021] In conjunction with the first aspect, in an optional embodiment of this application, the mass ratio of copper ion complexing agent to stannous salt is 2-4:1-2;

[0022] Optionally, the test solution includes 10-20 g / L of thiourea and 5-10 g / L of (CH3SO3)2Sn.

[0023] The potentials of stannous and copper ions change with the amount of complexing agent added. Adding a copper ion complexing agent and stannous salt at a mass ratio of 2-4:1-2 to the test solution can increase the potential of Sn ions. 2+ The rate of displacement reaction between ions and Cu results in the rapid precipitation of metallic tin.

[0024] Using a test solution containing 10-20 g / L thiourea and 5-10 g / L (CH3SO3)2Sn, the presence of residual adhesive in the first region of the solar cell substrate can be detected. In areas not covered by residual adhesive, the precipitation of metallic tin can be quickly observed, thereby quickly determining whether the solar cell substrate has incomplete development. Based on the test results, the exposure and development processes before the copper plating process of the solar cell can be adjusted in a timely manner, thus avoiding the appearance of a large number of defective copper grid lines after the electroplating process.

[0025] In conjunction with the first aspect, in an optional embodiment of this application, the method of covering the first area with the test liquid includes: immersing the solar cell substrate in the test liquid for a preset time;

[0026] Optionally, 3-5 solar cell substrates may be immersed in the test solution at the same time;

[0027] Optional, the preset time is 5-15 seconds;

[0028] And / or, methods for observing the color of the first region include:

[0029] Use a microscope to observe the color of the first region.

[0030] Immersing the solar cell substrate with partially removed photoresist layer in the testing solution for 5-15 seconds ensures uniform contact between the copper metal layer not covered by residual photoresist in the first area and the testing solution, while also avoiding reduced testing efficiency due to excessive immersion time. Furthermore, immersing multiple solar cell substrates with partially removed photoresist layer simultaneously in the testing solution can reduce testing errors and improve testing efficiency, with a simple and convenient operation.

[0031] Secondly, embodiments of this application provide an inspection apparatus for the inspection method provided in the first aspect, comprising:

[0032] The flower basket has multiple limiting clips spaced along its length inside, with a distance of 0.4-0.6cm between adjacent clips, so that the spacing between two adjacent solar cell substrates inserted into the flower basket is 0.4-0.6cm. The flower basket includes a base plate and side plates surrounding the base plate, both of which are hollow structures. A tank is used to store the test liquid. The flower basket can be selectively placed into or out of the tank.

[0033] The testing device is equipped with a tank for storing the testing liquid. The solar cell substrate to be tested can be inserted into and removed from the tank through a basket. After being immersed in the testing liquid in the tank for a certain period of time, it is separated from the testing liquid through the basket, so that the operator can carry out subsequent testing operations.

[0034] The bottom and side plates of the flower basket are both hollow structures, and the distance between two adjacent limiting clamps used to fix the solar cell substrates in the flower basket is 0.4-0.6cm. This allows the surface of each solar cell substrate to be in uniform contact with the test liquid when multiple solar cell substrates enter the tank below the liquid level through the flower basket, thereby improving the testing efficiency and quality.

[0035] In conjunction with the second aspect, in an optional embodiment of this application, at least one side of the flower basket is provided with a handle protruding from the top of the flower basket at a certain height away from the bottom plate, for lifting the flower basket into and out of the trough.

[0036] A handle is provided on one side of the basket so that operators can easily move the basket into and out of the tank, avoiding contact with the testing liquid inside the tank and thus improving testing safety.

[0037] In conjunction with the second aspect, in an optional embodiment of this application, the side plate includes a first side plate disposed along the length direction of the basket; the limiting clip includes a first toothed rack disposed on the inner wall of the bottom plate and a second toothed rack disposed on the first side plate; the first toothed rack and the second toothed rack are used to limit the adjacent sides of the battery cells in a one-to-one correspondence.

[0038] The bottom and side panels of the flower basket are equipped with toothed racks, which can place the solar cells between the corresponding teeth of the two racks to prevent multiple solar cell substrates inside the flower basket from stacking on each other. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of a solar cell.

[0041] Figure 2A This is a schematic diagram of the first type of residual adhesive distribution in a solar cell substrate after the copper interconnect technology development process.

[0042] Figure 2B This is a schematic diagram showing the second type of residual adhesive distribution in a solar cell substrate after the copper interconnect technology development process.

[0043] Figure 3 A schematic diagram of the first plane of a solar cell substrate after uniform contact with the test liquid using the test method provided in this application;

[0044] Figure 4 A schematic diagram of the testing device provided as an example in this application;

[0045] Figure 5 This is an optical image after detection in Example 1 of this application.

[0046] Icons: 10-Inspection device; 11-Basket; 111-Base plate; 112-Side plate; 113-Limiting clamp; 1131-First rack; 1132-Second rack; 114-Handle; 12-Slot body;

[0047] 2-Solar cell; 20-Solar cell substrate; 21-Copper seed layer; 22-Photosensitive adhesive layer; 23-First region; 24-Second region; 25-Residual adhesive; 30-Electroplated copper grid lines. Detailed Implementation

[0048] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application; the terms “comprising” and “having”, and any variations thereof, in the specification and the foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0050] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0051] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0052] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), and similarly, "multiple pieces" refers to two or more (including two pieces).

[0053] In the description of the embodiments of this application, the technical terms "middle", "length", "width", "thickness", "upper", "lower", "bottom", "inner", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of 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. Therefore, they should not be construed as limitations on the embodiments of this application.

[0054] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "connection" and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0055] In solar cell technology, silicon-based heterojunction solar cells are most notable for their high conversion efficiency, simple manufacturing process, and low temperature coefficient compared to traditional P-type monocrystalline / polycrystalline solar cells. Currently, one of the cutting-edge solar photovoltaic technologies is the use of copper interconnect technology to replace traditional silver paste printing.

[0056] Besides cost, another major advantage of copper interconnect technology over traditional silver paste printing technology is its ability to produce finer lines. One of the core technologies for achieving this finer line quality is the pattern transfer technology of wet-film photosensitive emulsion. In copper interconnect battery technology, wet-film photosensitive emulsion is used for printing, developing, and electroplating to create the copper grid lines of the battery cells, replacing traditional silver paste printing technology.

[0057] In some fabrication processes of copper interconnect grids for heterojunction solar cells:

[0058] (1) A copper seed layer 21 is deposited on the surface of a silicon substrate (the silicon substrate includes: a silicon layer (an intrinsic amorphous silicon layer and a P-type amorphous silicon thin film layer deposited on the front side of an N-type silicon substrate, and an intrinsic amorphous silicon layer and an N-type amorphous silicon thin film layer deposited on the back side) and a transparent conductive oxide thin film layer). Then, a photosensitive adhesive layer 22 is formed on the copper seed layer 21 to cover the copper seed layer 21. Hereinafter, the color of the copper seed layer 21 will be named the first color.

[0059] (2) Then expose and develop the photosensitive emulsion layer 22 in step (1) to remove the unwanted photosensitive emulsion and form the first region 23. Figure 3For ease of demonstration, the portion not in the first region 23 is named the second region 24. Then, copper electroplating is performed in the first region 23 to form the electroplated copper grid lines 30.

[0060] A schematic diagram of the structure of solar cell 2 is shown below. Figure 1 As shown. The solar cell 2 includes a solar cell substrate 20 and electroplated copper grid lines 30.

[0061] Normally, after exposure and development, a groove structure is formed, exposing the copper seed layer 22 in the first region 23, facilitating electroplating on the copper seed layer 22 to thicken the copper layer in that region and form grid lines. However, after exposure and development, residual adhesive 25 often forms in the first region 23 of the solar cell substrate 20 due to incomplete development. A schematic diagram of the distribution of residual adhesive 25 on the solar cell substrate 20 due to incomplete development is shown below. Figure 2A and Figure 2B As shown. In this diagram, the second region 24 is the region where the photosensitive adhesive layer 22 was not removed, and the first region 23 is the region formed after part of the photosensitive adhesive layer 22 was removed.

[0062] in, Figure 2A This indicates that a layer of residual adhesive 25 is fully covered in area 23 of the first zone; Figure 2B This indicates that a layer of residual adhesive 25 is partially covered at location 23 in the first area.

[0063] The residual adhesive 25 is a colorless and transparent organic polymer material, which cannot be observed with the naked eye when development residue occurs. When the first region 23 is observed directly with the naked eye, the copper seed layer 21 beneath the residual adhesive 25 can be seen through it. The presence of the residual adhesive 25 can cause defects such as broken grid lines in the electroplated copper grid lines 30 obtained in subsequent electroplating, which seriously affects the use of the solar cell 2.

[0064] Therefore, when using copper interconnect technology to fabricate solar cells 2, the solar cell substrate 20 is often inspected.

[0065] In existing technologies, testing methods typically include two types:

[0066] Firstly, after the copper grid lines are electroplated, they are inspected to check for any grid breaks or other issues. However, checking for grid breaks after electroplating is significantly delayed and cannot promptly reflect whether incomplete development will occur during the exposure and development process.

[0067] Secondly, to ensure timely inspection, slides are periodically taken after development, and the yellow areas after development are scanned using EDX (Energy Dispersive X-ray Spectroscopy). If carbon (C) is detected, it indicates incomplete development, allowing feedback to the development process to adjust development parameters and prevent further incomplete development. However, elemental scanning using EDX requires slide preparation, which is time-consuming and has high requirements. Furthermore, EDX equipment is expensive, and the inspection requires specialized personnel.

[0068] Based on this, this application provides a method for inspecting a solar cell substrate 20, which utilizes an inspection solution to uniformly contact the first region 23 formed after exposure and development of the solar cell substrate 20. Under the action of the inspection solution, the copper metal in the portion of the first region 23 not covered by residual adhesive 25 can chemically react with the inspection solution, exhibiting a second color different from the first color of copper metal. Therefore, the presence of residual adhesive 25 can be determined by observing the color of the first region 23.

[0069] If residual adhesive 25 is attached to a portion of the first region 23, the portion of copper metal covered by the residual adhesive 25 will not react with the testing solution due to the barrier effect of the adhesive 25, thus preserving that portion of copper metal. Because the residual adhesive 25 is transparent, after treatment with the testing solution, the portion covered by the residual adhesive 25 continues to exhibit the first color of copper metal, while the portion not covered by the residual adhesive 25 exhibits a second color different from the first color.

[0070] The inspection methods for solar cell substrate 20 include:

[0071] S1. Cover the first area 23 with the test solution.

[0072] Please continue reading. Figure 3 When there is no residual adhesive 25 in the first region 23, after the test solution is evenly covered in the first region 23, the copper metal in the first region 23 comes into direct contact with the test solution and reacts with the test solution. The first region 23 then presents a second color that is different from the first color of the copper metal.

[0073] Figure 3 In the image, for ease of display, white stripes are the primary color, and black stripes are the secondary color.

[0074] When a portion of the first region 23 is covered with residual adhesive 25, after the test solution is evenly applied to the first region 23, the test solution cannot directly contact the copper metal covered by the residual adhesive 25 due to the obstruction effect of the adhesive 25. Consequently, the copper metal beneath the adhesive 25 cannot react with the test solution and continues to exhibit the first color. However, the copper metal not covered by the adhesive 25, upon direct contact with the test solution, will react and exhibit a second color different from the first color. That is, the first region 23 exhibits both the first and second colors simultaneously.

[0075] When the first region 23 is completely covered with residual adhesive 25, after the test liquid is evenly covered in the first region 23, due to the blocking effect of the residual adhesive 25, the test liquid cannot directly contact the copper metal, and the first region 23 still shows the first color.

[0076] This application does not limit the specific type of test solution. Relevant personnel can make appropriate selections as needed, provided that the test solution can react with the copper metal in contact to produce a second color different from that of the copper metal, and does not react with the residual adhesive 25 in contact.

[0077] In one possible embodiment, the test solution comprises stannous salt and a copper ion complexing agent, and the pH of the test solution is not greater than 1.

[0078] The stannous ions in the stannous salt, under the combined action of a strong acidic environment and a copper ion complexing agent, can undergo a displacement reaction with the copper metal not covered by residual adhesive 25, causing metallic tin to precipitate on the surface of the copper metal in that area, resulting in a milky white color resembling metallic tin. That is, when using the test solution provided in this example to test for incomplete development, the second color is a milky white color resembling metallic tin.

[0079] Because tin is more reactive than copper in the metal activity series, under normal thermodynamic conditions, the more reactive tin can displace the less reactive copper from its salt solution, while the less reactive copper cannot displace the more reactive tin from its salt solution. However, the test solution provided in this example is a strongly acidic solution and includes a copper ion complexing agent. The copper ion complexing agent can react with the Cu ions in the first region 23 it contacts. 2+ Cu + The formation of stable complex ions alters the electrode potential of the reaction, thereby enabling the stannous ions to undergo a reduction reaction and precipitate metallic tin.

[0080] The overall reaction equation is shown below:

[0081] 2Cu+Sn 2+ →2Cu + +Sn

[0082] This application does not limit the specific type of copper ion complexing agent. In some possible embodiments, the copper ion complexing agent is selected from at least one of thiourea or citric acid.

[0083] For example, a copper ion complexing agent is thiourea (CH4N2S). The addition of thiourea forms [Cu(NH2CSNH2)4]. 2+ [Cu(NH2CSNH2)4] + Isocomial ions alter the electrode potential of the reaction.

[0084] Furthermore, the stannous salt can be (CH3SO3)2Sn.

[0085] Alternatively, the stannous salt can be a stannous halide or a stannous methanesulfonate.

[0086] Furthermore, this application does not limit the mass ratio of copper ion complexing agent to stannous salt in the test solution. In some possible embodiments, the mass ratio of thiourea to (CH3SO3)2Sn is 2-4:1-2.

[0087] For example, the test solution includes 10-20 g / L of thiourea and 5-10 g / L of (CH3SO3)2Sn.

[0088] For example, the test solution includes 10 g / L of thiourea and 5 g / L of (CH3SO3)2Sn.

[0089] For example, the test solution includes 20 g / L of thiourea and 5 g / L of (CH3SO3)2Sn.

[0090] Alternatively, the test solution may include a strong acid solution, such as concentrated sulfuric acid, concentrated hydrochloric acid, or concentrated nitric acid, to corrode or oxidize the copper metal not covered by residual adhesive 25, resulting in a second color different from metallic copper. However, the corrosion process of strong acid solutions is slow, leading to lower detection efficiency.

[0091] Alternatively, depending on the relative reactivity of the metals, a metal ion salt with weaker reactivity than copper can be added to the test solution. For example, the test solution may include a silver ion salt solution or a platinum ion salt solution.

[0092] Furthermore, this application does not limit how the test solution covers the first region 23. In some possible embodiments, the method of covering the first region 23 with the test solution includes:

[0093] The solar cell substrate 20 is immersed in the test solution for a preset time.

[0094] Furthermore, 3-5 solar cell substrates 20 can be immersed in the testing solution simultaneously to test multiple solar cell substrates 20, which can reduce the testing error.

[0095] Optionally, multiple solar cell substrates 20 can be simultaneously immersed in an acidic test solution containing a copper ion complexing agent and stannous salt provided in this example for 5-10 seconds.

[0096] Alternatively, a dropper or other chemical test tube can be used to drip a sufficient amount of test solution into the first region 23 of the solar cell substrate 20, ensuring that the test solution completely covers the first region 23. After a certain period of time, the test solution in the first region 23 can be absorbed using a pipette or absorbent cotton, and then quickly dried before subsequent observation.

[0097] Furthermore, in order to facilitate the simultaneous inspection of multiple solar cell substrates 20, an inspection device 10 is also provided in the present application.

[0098] Please see Figure 4 The testing device 10 includes:

[0099] The flower basket 11 has multiple limiting clips 113 spaced apart along its length inside. The distance between two adjacent limiting clips is 0.4-0.6cm, so that the two adjacent solar cell substrates 20 inserted into the flower basket 11 are spaced apart by 0.4-0.6cm. The flower basket 11 includes a base plate 111 and side plates 112 surrounding the base plate. Both the base plate 111 and the side plates 112 have a hollow structure.

[0100] The tank 12 is used to store the test solution; the basket 11 can be selected to enter and exit the tank 12.

[0101] Since the bottom plate 111 and side plate 112 of the flower basket 11 are both hollow structures, the test liquid in the tank 12 can flow into the interior of the flower basket 11. Furthermore, the spacing between two adjacent limiting clips 113 inside the flower basket 11 is 0.4-0.6cm, so when multiple solar cell substrates 20 are placed inside the flower basket 11, adjacent solar cell substrates 20 can be spaced 0.4-0.6cm apart, allowing multiple solar cell substrates 20 to contact the test liquid evenly.

[0102] This application does not restrict the specific setting of the flower basket 11, and relevant personnel can make corresponding adjustments as needed.

[0103] For example, the internal chamber of the flower basket 11 is cubic to accommodate the placement of a rectangular solar cell substrate 20.

[0104] Furthermore, the basket 11 includes a rectangular base plate 111 and four rectangular side plates 112 surrounding the base plate 111. Both the base plate 111 and the side plates 112 are provided with multiple through holes at intervals to increase the flow of the test solution. Alternatively, a rectangular through hole can be formed in the middle of the base plate 111 and the side plates 112 to further increase the flow of the test solution into the basket 11.

[0105] This application does not limit the specific arrangement of the limiting clip 113. In some possible embodiments, the limiting clip 113 includes a first rack 1131 disposed on the inner wall of the base plate 111 and a second rack 1132 disposed on one of the side plates 112; the first rack 1131 and the second rack 1132 are used to limit the two adjacent sides of the solar cell substrate 20 in a one-to-one correspondence.

[0106] Furthermore, a third rack can be provided on another side plate 112 opposite to one of the side plates 112 where the second rack 1132 is provided. The corresponding teeth of the three racks are used to jointly restrict the three edges of the solar cell substrate 20.

[0107] Furthermore, in order to facilitate the operator in lifting the basket 11 and avoid the operator from coming into contact with the test liquid in the tank 12, in one possible embodiment, a handle 114 for extending the side panel can be provided at one or more side panels 112 of the basket 11.

[0108] This application does not limit the specific configuration of the tank 12, and relevant personnel can make corresponding adjustments as needed.

[0109] In some possible implementations, a stirring element can be installed inside the tank 12 to properly stir and disperse the test liquid.

[0110] Furthermore, a heating element can be installed at the tank 12 to appropriately heat the test solution in the tank 12, thereby increasing the reaction rate between the test solution and metallic copper.

[0111] Furthermore, to facilitate subsequent observation, the inspection apparatus 10 provided in this example also includes a drying component and a microscope. The drying component is used to dry the soaked battery cells.

[0112] S2. Observe the color of the first copper region 23. Based on whether the color of the first region 23 changes, determine whether there is residual adhesive in the first region 23.

[0113] If the entire color of the first region 23 is the second color, it means that there is no residual adhesive 25 in the first region 23; if the first region 23 retains the first color, it means that there is residual adhesive 25 in the first region 23.

[0114] Specifically, if the entire color of the first region 23 is the second color, it means that the entire area to be tested coated with the test solution is the second color. For example, if the area to be tested is a quadrilateral, during testing, the test solution completely covers the quadrilateral. Then, the color within the quadrilateral area is observed. If the entire quadrilateral area is the second color, it indicates that there is no residual adhesive 25 within the quadrilateral area to be tested.

[0115] Similarly, if a portion of the first region 23 is the second color, it means that the second color appears within the quadrilateral region to be detected. The simultaneous appearance of the first and second colors within this quadrilateral region indicates the presence of residual adhesive 25.

[0116] If the first region 23 observed is entirely the first color of metallic copper, it indicates that the first region 23 is completely covered with a layer of residual adhesive 25.

[0117] If the first region 23 is observed to be entirely the second color, such as the milky white of metallic tin, it indicates that there is no residual adhesive 25 in the first region 23.

[0118] If the first region 23 is observed to have both the first color of metallic copper and the second color of metallic tin, it indicates that there is residual adhesive 25 in some parts of the first region 23.

[0119] Furthermore, this application does not limit how the color of the first region 23 is observed. In some possible embodiments, the method for observing the color of the first region 23 includes:

[0120] Use an industrial microscope or magnifying glass to observe the color of the first region 23.

[0121] Alternatively, the operator can directly observe it with the naked eye.

[0122] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0123] Example 1

[0124] Example 1 provides a method for inspecting a solar cell substrate 20, comprising:

[0125] (1) Immerse the exposed and developed solar cell substrate 20 in the test solution for 5 seconds, then take out the solar cell substrate 20 and blow it dry; wherein, the test solution is 10 g / L of (CH3SO3)2Sn and 5 g / L of CH4N2S, and the pH of the test solution is 1.

[0126] (2) Place the solar cell substrate 20 processed in step (1) onto the stage of an optical microscope and observe the color of the first region 23 of the solar cell substrate 20. The optical image of the solar cell substrate 20 is shown below. Figure 5 As shown, the optical image can be divided into three layers from top to bottom: the upper and lower layers are the second region 24, and the middle layer is the first region 23.

[0127] Figure 5In the image, the black frame contains residual adhesive 25, which gives the first color of the copper seed layer 21 (the optical image is blurrier than the surface of the grown tin metal due to the presence of transparent residual adhesive 25), indicating that there is some residual adhesive 25 in the detection area.

[0128] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for inspecting a solar cell substrate, the solar cell substrate comprising a copper seed layer and a photosensitive adhesive layer stacked together; wherein a portion of the solar cell substrate is subjected to a process of removing the photosensitive adhesive layer to form a first region; The testing method is used to test whether there is transparent residual adhesive in the first area; characterized in that, The testing method includes: The test solution is applied to the first area, and the color of the first area is observed; wherein the test solution contains a substance that can react with copper and change the color of the copper to a second color; The test solution is applied before covering the first area, where the first area is a first color; The presence of residual adhesive in the first area is determined by whether the color of the first area has completely changed: if the first area retains the first color, it indicates that there is residual adhesive in the first area; The test solution includes stannous salt and copper ion complexing agent, and the pH of the test solution is not greater than 1.

2. The inspection method for solar cell substrates according to claim 1, characterized in that, The first region is used for electroplating to thicken and form electroplated copper grid lines.

3. The inspection method for solar cell substrates according to claim 1, characterized in that, If the entire color of the first area is the second color, it means that the first area has no residual adhesive; if the entire color of the first area is the first color, it means that the first area is fully covered with the residual adhesive; if the color of the first area includes both the first color and the second color, it means that the first area is partially covered with the residual adhesive.

4. The inspection method for solar cell substrates according to claim 1, characterized in that, The copper ion complexing agent is selected from at least one of thiourea and citric acid.

5. The inspection method for solar cell substrates according to claim 4, characterized in that, The copper ion complexing agent is thiourea, and the stannous salt is (CH3SO3)2Sn.

6. The inspection method for solar cell substrates according to claim 5, characterized in that, The mass ratio of the copper ion complexing agent to the stannous salt is 2-4:1-2.

7. The inspection method for solar cell substrates according to claim 6, characterized in that, The test solution comprises 10-20 g / L of the thiourea and 5-10 g / L of the (CH3SO3)2Sn.

8. The method for inspecting solar cell substrates according to any one of claims 1-7, characterized in that, The method for covering the first area with the test solution includes: The solar cell substrate is immersed in the test solution for a preset time; And / or, the method for observing the color of the first region includes: Use a microscope to observe the color of the first area.

9. The inspection method for solar cell substrates according to claim 8, characterized in that, Simultaneously, 3-5 solar cell substrates are immersed in the test solution.

10. The inspection method for solar cell substrates according to claim 8, characterized in that, The preset time is 5-15 seconds.

11. An inspection apparatus for the inspection method of a solar cell substrate according to any one of claims 1-10, characterized in that, The testing device includes: The flower basket has multiple limiting clips spaced apart along its length inside, with a distance of 0.4-0.6 cm between two adjacent limiting clips, so that the spacing between two adjacent solar cell substrates inserted into the flower basket is 0.4-0.6 cm; the flower basket includes a base plate and side plates surrounding the base plate, both of which are hollow structures; A tank for storing the test solution; the flower basket can selectively enter and exit the tank.

12. The inspection device according to claim 11, characterized in that, At least one side of the flower basket is provided with a handle that protrudes from the top of the flower basket at a predetermined height away from the bottom plate, for lifting the flower basket into and out of the trough.

13. The inspection apparatus according to claim 11, characterized in that, The side plate includes a first side plate arranged along the length of the flower basket; the limiting clamp includes a first toothed rack disposed on the inner wall of the base plate and a second toothed rack disposed on the first side plate; the first toothed rack and the second toothed rack are used to limit the two adjacent sides of the solar cell substrate in a one-to-one correspondence.

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