A method and device for testing the performance of a film on a cell without a main grid

Abstract

This invention discloses a method and apparatus for testing the coating performance of grid-free solar cells, comprising: acquiring a sample to be tested; the sample to be tested includes a grid-free solar cell, a thin film disposed on at least one side of the grid-free solar cell, and a solder ribbon sandwiched between the grid-free solar cell and the thin film; performing a peel tensile strength test on the thin film and / or a pull-out tensile strength test on the solder ribbon according to the stage state of the sample to be tested; and determining the coating performance of the sample to be tested based on the tensile strength test results. This invention realizes coating performance testing for grid-free solar cell structures, which can effectively avoid the problems of solder ribbon misalignment and incomplete soldering in the subsequent lamination process of grid-free solar cells, and improve the production yield of grid-free solar cells.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a method and apparatus for testing the coating performance of gridless solar cells. Background Technology

[0002] With the development of photovoltaic module technology, solar cell busbar technology has gradually evolved from SuperMulti-Busbar (SMBB) to busbarless (0-Busbar, 0BB). Traditional SMBB cells all have busbars and PAD points. PAD points are used to complete electrical interconnection with solder ribbons during the stringing process.

[0003] However, since 0BB cells only have fine grids, they cannot be electrically interconnected using the traditional SMBB welding process. Therefore, performance testing for SMBB cells is not applicable to 0BB cells. Summary of the Invention

[0004] This invention provides a method and apparatus for testing the coating performance of grid-free solar cells, enabling coating performance testing of grid-free solar cell structures. This method can effectively avoid problems such as solder strip misalignment and incomplete soldering in the subsequent lamination process, thereby improving the production yield of grid-free solar cells.

[0005] In a first aspect, embodiments of the present invention provide a method for testing the coating performance of a grid-less solar cell, comprising:

[0006] Obtain the sample to be tested; the sample to be tested includes a grid-less solar cell, a thin film disposed on at least one side of the grid-less solar cell, and a solder strip sandwiched between the grid-less solar cell and the thin film;

[0007] Based on the stage state of the sample to be tested, the film is subjected to a peel tensile strength test, and / or the solder strip is subjected to a pull-out tensile strength test;

[0008] The coating performance of the sample under test is determined based on the tensile strength test results.

[0009] Optionally, the stage state includes a first state, which includes the state in which the thin film undergoes a cross-linking reaction to bond the solder ribbon to the gridless solar cell;

[0010] Based on the stage state of the sample to be tested, tensile performance tests are performed on the film and / or the solder strip, including:

[0011] When the sample to be tested is in the first state, the pull-out tensile strength test is performed on the solder strip, and / or, when the sample to be tested is in the first state, the peel tensile strength test is performed on the film.

[0012] Optionally, when the sample to be tested is in the first state, the pull-out tensile strength test is performed on the solder strip, including:

[0013] The sample to be tested is fixed;

[0014] Clamp one end of the welding strip on the same side of the sample to be tested, and pull the welding strip away along the extension direction of the welding strip to obtain the pulling force of each welding strip.

[0015] Optionally, when the sample to be tested is in the first state, the film is subjected to a peel strength test, including:

[0016] The sample to be tested is fixed;

[0017] Clamp one side of the film in the sample to be tested, and peel the film along one side of the film in the direction of the opposite side of the film to obtain the peeling tensile force of the film.

[0018] Optionally, the coating performance of the sample under test can be obtained based on the tensile performance test results, including:

[0019] The coating performance of the sample under test in the first state is determined based on the pull-out force of each of the solder strips; wherein, when the pull-out force of each of the solder strips is greater than the first preset force, it is determined that the sample under test meets the coating performance requirements in the first state.

[0020] or,

[0021] The coating performance of the sample under test in the first state is determined based on the peel strength of the film; wherein, when the peel strength of the film is greater than a second preset strength, the sample under test is determined to meet the coating performance requirements in the first state.

[0022] or,

[0023] The coating performance of the sample under test in the first state is determined based on the pull-out force of each solder strip and the peeling force of the film; wherein, when the pull-out force of each solder strip is greater than the first preset force and the peeling force of the film is greater than the second preset force, the sample under test is determined to meet the coating performance requirements in the first state.

[0024] Optionally, the stage state includes a second state, which includes a state in which the thin film, the solder ribbon, and the gridless cell have undergone a lamination process, and the solder ribbon and the gridless cell are electrically interconnected.

[0025] When the sample to be tested is in the first state, after performing a pull-out tensile strength test on the solder strip and / or a peel tensile strength test on the film, the method further includes:

[0026] When the sample to be tested is in the second state, the peel strength performance test is performed on the film.

[0027] Optionally, when the sample to be tested is in the second state, the film is subjected to a peel strength test, including:

[0028] The sample to be tested is fixed;

[0029] A pre-cut layered strip extends inward from one side of the film, parallel to the extension direction of the solder strip, and the layered strip separates part of the gridless solar cell from the film;

[0030] Clamp the layer strip and peel it off along one side of the film towards the opposite side of the film to obtain the peeling tensile force of the film.

[0031] Optionally, before fixing the sample to be tested, the following steps are included:

[0032] The test sample is prepared by laminating the sample into a test laminate structure, which includes a glass substrate, a first transparent film, a second transparent film, and a back plate stacked together; the test sample is placed between the first transparent film and the second transparent film.

[0033] The test stack structure also includes an isolation membrane, at least a portion of which is disposed between the thin film and the solder strip of the sample under test;

[0034] A pre-cut layered strip extends inward from one side of the film, parallel to the extension direction of the solder ribbon. This layered strip separates a portion of the gridless solar cell from the film, including:

[0035] The layered strip is cut from at least a portion of the separating film on one side surface of the backplate, wherein the backplate, the second transparent film, and the thin film adjacent to the second transparent film are cut simultaneously to form the layered strip.

[0036] Optionally, the coating performance of the sample under test can be obtained based on the tensile performance test results, including:

[0037] The coating performance of the sample under test in the second state is determined based on the peel strength of the film; wherein, when the sample under test meets the coating performance requirements in the first state and the peel strength of the film is greater than a third preset strength, it is determined that the sample under test meets the coating performance requirements.

[0038] Secondly, embodiments of the present invention provide a coating performance testing device for grid-free solar cells, comprising:

[0039] An acquisition module is used to acquire a sample to be tested; the sample to be tested includes a grid-less solar cell, a thin film disposed on one side of the grid-less solar cell, and a solder strip sandwiched between the grid-less solar cell and the thin film;

[0040] The testing module is used to perform tensile performance testing on the film and / or the solder strip according to the stage state of the sample to be tested.

[0041] The judgment module is used to judge the coating performance of the sample under test based on the test results of tensile performance.

[0042] The coating performance testing method for grid-less solar cells provided in this invention obtains a sample to be tested. Considering the structure of the sample itself, tensile performance tests can be performed on the thin film and / or solder ribbon for samples at different stages to reflect the coating performance of the sample. Finally, the coating performance of the sample is judged based on the tensile performance test results. This method realizes coating performance testing for grid-less solar cell structures, which can effectively avoid the problems of solder ribbon misalignment and poor soldering in the subsequent lamination process of grid-less solar cells, and improve the production yield of grid-less solar cells. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of an SMBB solar cell in related technologies;

[0044] Figure 2 This is a schematic diagram of the electrical interconnection between SMBB cells and solder ribbons in related technologies;

[0045] Figure 3 This is a schematic diagram of the structure of an OBB battery cell provided in an embodiment of the present invention;

[0046] Figure 4 This is a schematic diagram of the electrical interconnection between an OBB battery cell and a solder strip, provided as an embodiment of the present invention.

[0047] Figure 5 A schematic flowchart illustrating a method for testing the coating performance of a gridless solar cell according to an embodiment of the present invention;

[0048] Figure 6 A flowchart illustrating another method for testing the coating performance of a gridless solar cell provided in an embodiment of the present invention;

[0049] Figure 7 This is a schematic diagram of a structure for testing the strip pull-out force of a gridless solar cell according to an embodiment of the present invention;

[0050] Figure 8 A flowchart illustrating another method for testing the coating performance of a gridless solar cell provided in an embodiment of the present invention;

[0051] Figure 9 This is a schematic diagram of a structure for testing the thin film peel force of a gridless solar cell according to an embodiment of the present invention;

[0052] Figure 10 This is a schematic diagram of data related to the improvement of tensile process provided in an embodiment of the present invention;

[0053] Figure 11 A flowchart illustrating another method for testing the coating performance of a gridless solar cell provided in an embodiment of the present invention;

[0054] Figure 12 This is a schematic diagram of another method for testing the peel force of a gridless solar cell film 220 according to an embodiment of the present invention;

[0055] Figure 13 A schematic diagram of peeling reliability provided for an embodiment of the present invention;

[0056] Figure 14 A schematic diagram of the structure of a test sample is provided for embodiments of the present invention;

[0057] Figure 15 A schematic diagram of the layered strip structure in the test sample is provided for embodiments of the present invention;

[0058] Figure 16 This is a schematic diagram of the structure of a coating performance testing device for gridless solar cells provided in an embodiment of the present invention. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] With the development of photovoltaic module technology, solar cell busbar technology is gradually evolving from SMBB to OBB. Figure 1 This is a schematic diagram of the structure of an SMBB solar cell in related technologies. Figure 2 This is a schematic diagram of the electrical interconnection between SMBB solar cells and solder ribbons in related technologies. Traditional SMBB solar cells all have a main busbar 110 and a PAD point 120. During the stringing process, the solder ribbon 130 is baked at high temperature by the infrared lamp box of the welding machine, and the surface tin layer melts and combines with the PAD point 120 to complete the electrical interconnection.

[0061] Figure 3This is a schematic diagram of the structure of an OBB battery cell provided in an embodiment of the present invention. Figure 4 This is a schematic diagram of an 0BB battery cell and solder ribbon electrical interconnection provided by an embodiment of the present invention. The 0BB battery cell only has a fine grid 210. To achieve electrical interconnection, a thin film 220 can be deposited on the 0BB battery cell. For example, the thin film 220 can be an EVA film. Solder ribbon 130 is attached to the thin film 220 and the 0BB battery cell. After the thin film 220 passes through the high temperature of the infrared lamp box of the welding machine, a cross-linking reaction occurs, tightly adhering the solder ribbon 130 to the surface of the battery cell. During the lamination stage, the tin layer on the surface of the solder ribbon 130 melts at high temperature and completes the electrical interconnection with the 0BB battery cell. The performance test of SMBB (Surface Mount Battery Cell) characterizes the effectiveness of the electrical interconnection between the battery and the solder ribbon 130 by the force of the solder ribbon 130 separating from the PAD point 120. However, since there is no direct interconnection force between the 0BB solder ribbon 130 and the battery cell, the traditional SMBB battery cell performance test is no longer applicable to 0BB battery cells. Therefore, a new test method is needed to test the effectiveness of the coating bonding of the 0BB battery cell.

[0062] In view of this, Figure 5 This is a flowchart illustrating a method for testing the coating performance of a busbarless solar cell according to an embodiment of the present invention. This embodiment is applicable to the coating performance testing of busbarless solar cells. The method can be executed by a testing device for the coating performance of busbarless solar cells, which can be implemented in hardware and / or software. The method specifically includes the following steps:

[0063] S110. Obtain the sample to be tested; the sample to be tested includes a grid-less solar cell, a thin film 220 disposed on at least one side of the grid-less solar cell, and a solder ribbon 130 sandwiched between the grid-less solar cell and the thin film 220.

[0064] The test samples can be normally produced grid-less solar cells, using the produced grid-less solar cells for testing, or they can be small test samples prepared separately with the same production process parameters. See also Figure 3 and Figure 4 The sample to be tested may include a gridless solar cell 200, a thin film 220, and solder ribbons 130. The gridless solar cell 200 is provided only with fine grids 210, which can be arranged in parallel. At least one side of the gridless solar cell 200 is covered with the thin film 220, which can cover the gridless solar cell 200. Solder ribbons 130 are disposed between the gridless solar cell 200 and the thin film 220. For example, the solder ribbons 130 can be arranged at intervals perpendicular to the fine grids 210.

[0065] S120. Based on the stage state of the sample to be tested, perform a peel tensile strength test on the film 220 and / or a pull-out tensile strength test on the solder strip 130.

[0066] Specifically, the stage state can refer to the intermediate structural state of the sample under test in a certain production process. For the sample under test in different stage states, the tensile performance test of the film 220 and / or the solder strip 130 is selected in a targeted manner to reflect the coating performance of the sample under test.

[0067] For example, a thin film 220 is laid on the gridless solar cell 200. After being subjected to high temperature in the infrared lamp box of the welding machine, the thin film 220 undergoes a cross-linking reaction. At the stage where the thin film 220 tightly adheres the solder ribbon 130 to the surface of the solar cell, the peel strength of the thin film 220 can be tested. The peel strength reflects the coating pressure. Better coating performance ensures better stability in the relative position between the solder ribbon 130 and the gridless solar cell 200, thus avoiding problems such as solder ribbon misalignment and incomplete soldering during subsequent lamination processes. At the same stage, the coating performance can also be reflected by the pull-out strength of the solder ribbon 130. For example, a greater pull-out strength indicates better friction between the solder ribbon 130 and the thin film 220, and between the solder ribbon 130 and the gridless solar cell 200, thereby ensuring better stability in the relative position between the solder ribbon 130 and the gridless solar cell 200. After the lamination process, when the solder ribbon 130 and the gridless cell 200 have completed the corresponding stage of electrical interconnection, the peel strength test of the film 220 can be performed to ensure the adhesion performance of the gridless cell after lamination and to ensure the effectiveness of the electrical material bonding force of the gridless cell.

[0068] S130. Determine the coating performance of the sample to be tested based on the tensile performance test results.

[0069] Specifically, after performing a peel strength test on the film 220, the corresponding peel strength value can be obtained. A standard value is set according to the stage state of the sample to be tested, and the coating performance of the sample to be tested can be reflected by the relationship between the peel strength value and the standard value.

[0070] After performing a pull-out tensile test on the solder strip 130, the corresponding pull-out tensile value can be obtained. Another standard value is set according to the stage state of the sample to be tested. The coating performance of the sample to be tested can be reflected by the relationship between the pull-out tensile value and the standard value.

[0071] In some embodiments, the peel tensile strength test result can be used as the primary standard to determine the coating performance of the sample under test. For example, if the peel tensile strength value meets the requirements, it can be said that the coating performance of the sample under test meets the requirements. Similarly, the pull-out tensile strength test result can be used as the primary standard to determine the coating performance of the sample under test. For example, if the pull-out tensile strength value meets the requirements, it can be said that the coating performance of the sample under test meets the requirements. Alternatively, the peel tensile strength test result and the pull-out tensile strength test result can be used together as a correlated standard to determine the coating performance of the sample under test. For example, if both the peel tensile strength value and the pull-out tensile strength value meet the standards, it can be said that the coating performance of the sample under test meets the requirements.

[0072] The coating performance testing method for grid-less solar cells provided in this invention obtains a sample to be tested. Considering the structure of the sample itself, tensile performance tests can be performed on the thin film 220 and / or the solder ribbon 130 for samples at different stages to reflect the coating performance of the sample. Finally, the coating performance of the sample is judged based on the tensile performance test results. This method realizes coating performance testing for grid-less solar cell structures, which can effectively avoid the problems of solder ribbon misalignment and poor soldering in the subsequent lamination process of grid-less solar cells, and improve the production yield of grid-less solar cells.

[0073] Optionally, the stage states include a first state, which includes the state in which the thin film 220 has undergone a cross-linking reaction to bond the solder ribbon 130 to the gridless cell 200.

[0074] Based on the stage state of the sample to be tested, tensile performance tests are performed on the film 220 and / or the solder strip 130, including:

[0075] When the sample to be tested is in the first state, the pull-out tensile strength test is performed on the solder strip 130, and / or, when the sample to be tested is in the first state, the peel tensile strength test is performed on the film 220.

[0076] Specifically, according to the manufacturing process of gridless solar cells, in order to achieve electrical interconnection, a thin film 220 is typically laid on the gridless solar cell 200. For example, the thin film 220 can be an EVA film. After passing through the high temperature of the infrared lamp box of the welding machine, the thin film 220 undergoes a cross-linking reaction, tightly adhering the solder ribbon 130 to the surface of the solar cell. At this stage, better coating performance allows for better stability in the relative position between the solder ribbon 130 and the gridless solar cell 200, thereby avoiding problems such as solder ribbon misalignment and incomplete soldering during subsequent lamination processes. Therefore, this stage can be considered the first state. In the first state, the peel strength of the thin film 220 can be tested. The peel strength reflects the coating pressure, and better coating pressure allows for better stability in the relative position between the solder ribbon 130 and the gridless solar cell 200. And / or, in the first state, the pull-out pull performance test of the solder ribbon 130 can also be performed. The greater the pull-out pull of the solder ribbon 130, the better the friction between the solder ribbon 130 and the thin film 220 and between the solder ribbon 130 and the gridless cell 200, thereby ensuring better stability in the relative position between the solder ribbon 130 and the gridless cell 200.

[0077] Based on the above embodiments, Figure 6 A flowchart illustrating another method for testing the coating performance of a grid-less solar cell according to an embodiment of the present invention is provided. (See attached diagram.) Figure 6 ,include:

[0078] S210. Obtain the sample to be tested in the first state; the sample to be tested includes a grid-less solar cell 200, a thin film 220 on at least one side of the grid-less solar cell 200, and a solder strip 130 sandwiched between the grid-less solar cell 200 and the thin film 220.

[0079] S220. Fix the sample to be tested;

[0080] Specifically, Figure 7 This is a schematic diagram of a structure for testing the strip pull-out force of a grid-less solar cell according to an embodiment of the present invention. (See attached diagram.) Figure 7 The sample to be tested is placed on the tensile testing machine platform 330 and fixed using a fixing device. For example, the fixing device can consist of multiple pressure rollers 310 arranged parallel to the welding strip 130 at intervals. The pressure rollers 310 should not press directly onto the welding strip 130 to avoid introducing testing errors. A stop 320 can also be provided at the edge of the sample to block it and prevent it from sliding along the extraction direction during the extraction process of the welding strip 130.

[0081] S230: Clamp one end of the welding strip 130 on the same side of the sample to be tested, and pull the welding strip 130 away along the extension direction of the welding strip 130 to obtain the pulling force of each welding strip 130.

[0082] Specifically, each weld strip 130 is clamped by the clamping head 340 of the tensile testing machine, and the clamping head is pulled away from the weld strip 130 along the extension direction of the weld strip 130, so as to... Figure 7 For example, the clamp 340 pulls the solder strip 130 away from the film 220 in a horizontal rightward direction until the solder strip 130 is completely pulled out of the film 220, thereby obtaining the pulling force of each solder strip 130.

[0083] S240. Determine the coating performance of the sample under test in the first state based on the pull-out force of each solder strip 130; wherein, when the pull-out force of each solder strip 130 is greater than the first preset force, it is determined that the sample under test meets the coating performance requirements in the first state.

[0084] Specifically, a greater pull-out force of the solder ribbon 130 indicates better friction between the solder ribbon 130 and the thin film 220, as well as between the solder ribbon 130 and the gridless solar cell 200. This ensures better stability in the relative position between the solder ribbon 130 and the gridless solar cell 200, thus avoiding solder ribbon misalignment and cold solder joints during subsequent lamination. The coating performance of the sample is judged by determining the pull-out force of each solder ribbon 130. When the pull-out force of each solder ribbon 130 is greater than a first preset force, the coating performance requirements are considered met. Based on the correlation between numerous test experiments and the occurrence of solder ribbon misalignment and cold solder joints, the first preset force can be set to 2.5N. That is, when the pull-out force of each solder ribbon 130 is greater than 2.5N, the coating performance requirements are considered met. When the gridless solar cell 200 in the test sample is provided with thin films 220 on both sides, and the gridless solar cell 200 is sandwiched with solder strips 130 between the thin films 220 on both sides, the pull-out force of each solder strip 130 on both sides is required to be greater than the first preset pull force.

[0085] Based on the above embodiments, Figure 8 A flowchart illustrating another method for testing the coating performance of a grid-less solar cell according to an embodiment of the present invention is provided. (See attached diagram.) Figure 8 ,include:

[0086] S310. Obtain the sample to be tested in the first state; the sample to be tested includes a gridless solar cell 200, a thin film 220 on at least one side of the gridless solar cell 200, and a solder strip 130 sandwiched between the gridless solar cell 200 and the thin film 220.

[0087] S320. Fix the sample to be tested;

[0088] Specifically, Figure 9 This is a schematic diagram of a thin film peel force test for a gridless solar cell provided in an embodiment of the present invention. (See attached diagram.) Figure 9The sample to be tested is placed on the tensile testing machine platform 330 and fixed using a fixing device. For example, the fixing device can be at least two pressure rollers 310, which are placed on opposite sides of the sample to be tested. The film 220 on opposite sides of the sample to be tested is peeled off 5-10mm in advance to avoid the pressure rollers 310 fixing the film 220 and increasing the measurement error.

[0089] S330: Clamp one side of the film 220 in the sample to be tested, and peel off the film 220 in the direction from one side of the film 220 to the opposite side of the film 220 to obtain the peeling tensile force of the film 220.

[0090] Specifically, the pre-peeled film 220 of the sample to be tested is clamped by the jaws 340 of a tensile testing machine. The jaws 340 may have serrated edges to prevent slippage after clamping the film 220, which would affect the test results. The jaws 340 can peel the film 220 along one side towards the opposite side. Figure 9 For example, the clamp head 340 moves horizontally to the right to begin peeling off the film 220 until the film 220 is completely peeled off, thus obtaining the peeling pull force of the film 220.

[0091] S340. Determine the coating performance of the sample under test in the first state based on the peeling tensile force of the film 220; wherein, when the peeling tensile force of the film 220 is greater than the second preset tensile force, it is determined that the sample under test meets the coating performance requirements in the first state.

[0092] Specifically, the greater the peel strength of the film 220, the greater the coating pressure of the film 220. Better coating performance can make the relative position between the solder ribbon 130 and the gridless cell 200 more stable, thereby avoiding problems such as solder ribbon misalignment and poor soldering in the subsequent lamination process.

[0093] The coating performance of the sample under test is determined by judging the peel strength of the film 220. When the peel strength of the film 220 is greater than the second preset tensile strength, the coating performance requirements can be considered met. Based on numerous test experiments and the correlation with solder ribbon misalignment and poor soldering, the second preset tensile strength can be set to 2.5N. That is, when the peel strength of the film 220 is greater than 2.5N, the coating performance requirements can be considered met. When the busbarless solar cell 200 in the sample under test has films 220 on both sides, or when solder ribbons 130 are sandwiched between the busbarless solar cell 200 and the films 220 on both sides, the peel strength of the films 220 on both sides must be the second preset tensile strength.

[0094] Based on the above embodiments, in the first state of the test sample, the pull-out force of the solder ribbon 130 and the peel-off force of the thin film 220 are correlated. That is, the greater the pull-out force of the solder ribbon 130, the better the friction between the solder ribbon 130 and the thin film 220, and between the solder ribbon 130 and the gridless solar cell 200. The better friction can reflect the coating pressure of the thin film 220. The greater the peel-off force of the thin film 220, the greater the coating pressure of the thin film 220, which can also be reflected in the friction between the solder ribbon 130 and the gridless solar cell 200.

[0095] Therefore, when the sample to be tested is in its first state, the pull-out tensile strength test can be performed on the solder ribbon, and the peel tensile strength test can be performed on the film. The coating performance of the sample in the first state is determined based on the pull-out tensile strength of each solder ribbon and the peel tensile strength of the film. That is, by utilizing the correlation between the pull-out tensile strength of the solder ribbon 130 and the peel tensile strength of the film 220, and by limiting the pull-out tensile strength of each solder ribbon 130 to be greater than a first preset tensile strength and the peel tensile strength of the film 220 to be greater than a second preset tensile strength, solder ribbon misalignment and incomplete soldering problems can be better avoided. For example, Figure 10 This is a data illustration of the improved tensile process provided in an embodiment of the present invention. See also: Figure 10 In the first state of the test sample, when the pull-out force of solder ribbon 130 and the peel force of film 220 are 0.8N, the defect rate of cold solder joint is 4.08%, and the defect rate of solder ribbon misalignment is 2.03%; when the pull-out force of solder ribbon 130 and the peel force of film 220 are 1.5N, the defect rate of cold solder joint is 2.11%, and the defect rate of solder ribbon misalignment is 0.74%; when the pull-out force of solder ribbon 130 and the peel force of film 220 are 2N, the defect rate of cold solder joint is 0.84%, and the defect rate of solder ribbon misalignment is... The defect rate for cold solder joints is 0.29% when the pull-out force of the solder ribbon 130 and the peel-out force of the film 220 are 2.5N, and the defect rate for solder ribbon misalignment is 0.20%. When the pull-out force of the solder ribbon 130 and the peel-out force of the film 220 are 3N, the defect rate for cold solder joints is 0.33%, and the defect rate for solder ribbon misalignment is 0.17%. When the pull-out force of the solder ribbon 130 and the peel-out force of the film 220 are 3.5N, the defect rate for cold solder joints is 0.31%, and the defect rate for solder ribbon misalignment is 0.16%. Based on a large amount of test data and the correlation analysis of solder ribbon misalignment and cold solder joints, the first and second preset tension forces can be set to 3N. That is, when the pull-out force of each solder ribbon 130 and the peel-out force of each film 220 are greater than 3N, the problems of solder ribbon misalignment and cold solder joints can be better avoided.

[0096] Optionally, the stage state also includes a second state, which includes a state in which the thin film 220, the solder ribbon 130 and the gridless cell 200 have undergone a lamination process, and the solder ribbon 130 and the gridless cell 200 are electrically interconnected.

[0097] When the sample to be tested is in its first state, the pull-out tensile strength test is performed on the solder strip 130, and / or, after the peel tensile strength test is performed on the film 220 when the sample to be tested is in its first state, the test further includes:

[0098] When the sample to be tested is in the second state, the peel strength performance of film 220 is tested.

[0099] Specifically, after the first stage, the electrical interconnection between the gridless solar cell 200 and the solder ribbon 130 is completed through a lamination process. During lamination, the tin layer on the surface of the solder ribbon 130 melts at high temperature and completes the electrical interconnection with the gridless solar cell 200. In this stage, good coating performance ensures the adhesion performance of the gridless solar cell after lamination, guaranteeing the effectiveness of the electrical material bonding force. Therefore, this stage can be considered the second stage. After the sample meets the coating performance requirements in the first stage, the peel strength of the film 220 can be tested in the second stage. Peel strength reflects the coating pressure; good coating pressure ensures the effectiveness of the electrical material bonding force of the gridless solar cell, further guaranteeing the coating performance.

[0100] Based on the above embodiments, Figure 11 This is a flowchart illustrating another method for testing the coating performance of a grid-less solar cell according to an embodiment of the present invention, combined with... Figure 7 and Figure 9 See Figure 11 ,include:

[0101] S410. Obtain the sample to be tested in the first state; the sample to be tested includes a grid-less solar cell 200, a thin film 220 on at least one side of the grid-less solar cell 200, and a solder strip 130 sandwiched between the grid-less solar cell 200 and the thin film 220.

[0102] S420, respectively, the pull-out tensile strength test is performed on the solder strip 130, and the peel tensile strength test is performed on the film 220;

[0103] S430. Determine the coating performance of the sample under test in the first state based on the pull-out force of each solder strip and the peeling force of the film.

[0104] S440. Obtain the sample to be tested in the second state. The sample to be tested includes a grid-less solar cell 200, a thin film 220 on at least one side of the grid-less solar cell 200, and a solder ribbon 130 sandwiched between the grid-less solar cell 200 and the thin film 220.

[0105] S450. Fix the sample to be tested;

[0106] Specifically, Figure 12This is a schematic diagram of another type of peel force test for a gridless solar cell film 220 provided in an embodiment of the present invention. See also... Figure 12 The sample to be tested is fixed by a fixing device. For example, the fixing device can adopt at least two clamping units 410, with clamping units 410 respectively provided on opposite sides of the sample to be tested, so as to vertically clamp and fix the sample to be tested.

[0107] S460, a pre-cut layered strip 420 extends inward from one side of the thin film 220 in a direction parallel to the extension direction of the solder strip 130, and the layered strip 420 separates part of the gridless cell 200 and the thin film 220.

[0108] Specifically, a pre-defined layered strip 420 is cut from one side of the sample to be tested. The long side of the layered strip 420 is parallel to the extension direction of the solder strip 130 to avoid damaging the solder strip during cutting. The layered strip 420 is cut to the depth of the thin film 220, and the thin film 220 in the corresponding area of ​​the layered strip 420 is separated by peeling.

[0109] S470, clamp the delamination strip 420 and peel off the delamination strip 420 in the direction from one side of the film 220 to the opposite side of the film 220 to obtain the peeling pull of the film 220.

[0110] Specifically, one end of the delaminated strip 420 is clamped by the clamping head 340 of the tensile testing machine. The clamping head 340 may have serrations to prevent slippage after clamping the film 220, which would affect the test results. The clamping head 340 can peel the film 220 along one side of the film 220 towards the opposite side. Figure 12 For example, the clamp head 340 moves vertically upward to begin peeling off the film 220 until the film 220 is completely peeled off, thereby obtaining the peeling pull force of the film 220.

[0111] S480. Determine the coating performance of the sample under test in the second state based on the peeling tensile force of the film 220; wherein, when the sample under test meets the coating performance requirements in the first state and the peeling tensile force of the film 220 is greater than the third preset tensile force, it is determined that the sample under test meets the coating performance requirements.

[0112] Specifically, the greater the peeling force of the thin film 220, the better the film covering performance of the sample to be tested after the main-gridless cell 200 and the welding strip 130 complete electrical interconnection. The peeling force of the thin film 220 can directly reflect the effectiveness of the combination of electrical materials. The greater the peeling force of the thin film 220, the better the combination of the thin film 220, the welding strip 130, and the main-gridless cell 200 in the finished sample to be tested, the lower the outdoor failure risk, and the higher the reliability. That is to say, the film covering performance of the sample to be tested can be judged by judging the peeling force of the thin film 220. When the pulling force for extracting each welding strip 130 is greater than the first preset force, the peeling force of the thin film 220 is greater than the second preset force, and the peeling force of the thin film 220 is greater than the third preset force, it can be considered that the film covering performance requirements are met. Among them, based on a large number of test experiments and the correlation with welding strip offset and virtual welding, the third preset force can be set to 60N. That is to say, when the peeling force of the thin film 220 is greater than 60N, it can be considered that the film covering performance requirements are met.

[0113] Based on the above embodiments, there is a certain correlation between the peeling force of the thin film 220 of the sample to be tested in the second state and the pulling force for extracting the welding strip 130 and the peeling force of the thin film 220 of the sample to be tested in the first state. The greater the pulling force for extracting the welding strip 130 and the peeling force of the thin film 220 of the sample to be tested in the first state, the greater the peeling force of the thin film 220 of the sample to be tested in the second state. And the peeling force of the thin film 220 of the sample to be tested in the second state can directly reflect the effectiveness of the combination of electrical materials of the sample to be tested. Exemplarily, according to the IEC standard, a TC (thermal cycle reliability) test is performed. It is considered qualified when the defective rate of TC200 meets <5%. Among them, TC200 refers to 200 thermal cycle tests. For example, a TC200 test from -40° to 80° and then to -40°C is a cycle period, and the time for each cycle does not exceed 6 hours, and 200 cycles are performed. Through a large number of test experiments, Figure 13 is a data schematic diagram of the peeling reliability provided by the embodiment of the present invention. Refer to Figure 13 , for the sample to be tested in the second state, the defective rate data of TC50, TC100, TC150, and TC200 are respectively tested. Among them, TC50, TC100, and TC150 are 50 thermal cycle tests, 100 thermal cycle tests, and 150 thermal cycle tests respectively. According to the data, when the peeling force of the thin film 220 is 60N, TC200 <5% is satisfied. That is to say, when the peeling force of the thin film 220 is greater than 60N, the effectiveness of the combination of electrical materials of the sample to be tested is better.

[0114] Optionally, before fixing the sample to be tested in S450, it includes:

[0115] The test sample is prepared by laminating the test sample in the test laminate structure, which includes a glass substrate 520, a first transparent film 530, a second transparent film 540 and a back plate 510 stacked together; the test sample is placed between the first transparent film 530 and the second transparent film 540.

[0116] The test stack structure also includes a separator 550, at least a portion of which is disposed between the thin film 220 and the solder strip 130 of the sample under test;

[0117] A pre-cut layered strip 420 extends inward from one side of the thin film 220, parallel to the extension direction of the solder ribbon 130. The layered strip 420 separates part of the gridless solar cell 200 from the thin film 220, including:

[0118] Layered strips 420 are cut on one side surface of the backplate 510 in at least a portion of the release film 550, wherein the backplate 510, the second transparent film 540 and the thin film 220 adjacent to the second transparent film 540 are cut simultaneously to form the layered strips 420.

[0119] Specifically, in order to facilitate the testing of the peel strength of the film 220 of the test sample after electrical interconnection, a test sample can be prepared using the test sample. Figure 14 A schematic diagram of the structure of the test sample is provided for an embodiment of the present invention. See also Figure 14 The test sample includes a test sample and a test laminate structure. The test laminate structure includes a glass substrate 520, a first transparent adhesive film 530, a second transparent adhesive film 540, and a backplate 510 stacked together. For example, the glass substrate 520, backplate 510, first transparent adhesive film 530, and second transparent adhesive film 540 are all 40×40cm in size. A test sample 560 is placed between the first transparent adhesive film 530 and the second transparent adhesive film 540. The film 220 of the test sample 560 near the backplate 510 is torn open along the edge by about 40-60mm. A 60×200mm release film 550 is placed between the film 220 and the solder ribbon 130, and then lamination is performed to complete the preparation of the test sample.

[0120] Figure 15 A schematic diagram of the layered strip structure in the test sample is provided for an embodiment of the present invention. See [link / reference]. Figure 15Using a cutting tool, at least one layer strip 420 is cut along the side edge of the backplate 510 of the test sample in the area of ​​the separator 550. The backplate 510, the second transparent adhesive film 540, and the film 220 adjacent to the second transparent adhesive film 540 are cut simultaneously. The separator 550 serves a protective function, preventing the cutting process from cutting the lower solder strip 130 and the gridless cell 200. During subsequent tensile testing, the film 220 can be separated by pulling the layer strip 420. For example, to facilitate clamping with pliers 340, the width of the layer strip 420 can be 20-40 mm, wherein the length direction of the layer strip 420 is parallel to the extension direction of the solder strip 130.

[0121] Figure 16 This is a schematic diagram of a coating performance testing device for a grid-less solar cell according to an embodiment of the present invention. (See attached diagram.) Figure 16 ,include:

[0122] The acquisition module 610 is used to acquire the sample to be tested; the sample to be tested includes a grid-less solar cell 200, a thin film 220 on one side of the grid-less solar cell 200, and a solder ribbon 130 sandwiched between the grid-less solar cell 200 and the thin film 220.

[0123] The test module 620 is used to perform tensile performance tests on the film 220 and / or the solder strip 130 according to the stage state of the sample to be tested.

[0124] The judgment module 630 is used to judge the coating performance of the sample under test based on the test results of tensile performance.

[0125] Specifically, the acquisition module 610 is used to acquire the sample to be tested. The sample can be a normally produced grid-less solar cell, which is then used for testing, or it can be a test sample prepared separately with the same production process parameters. The sample to be tested includes a grid-less solar cell 200, a thin film 220, and solder ribbons 130. The grid-less solar cell 200 only has fine grids, which can be arranged in parallel. At least one side of the grid-less solar cell 200 is covered with the thin film 220, which can cover the grid-less solar cell 200. The solder ribbons 130 are disposed between the grid-less solar cell 200 and the thin film 220. For example, the solder ribbons 130 can be arranged perpendicular to the fine grids.

[0126] The stage state can refer to the intermediate structural state of the sample under test in a certain production process. The test module 620 selects to perform tensile performance tests on the film 220 and / or the solder strip 130 for the sample under test in different stage states, so as to reflect the coating performance of the sample under test.

[0127] For example, when a thin film 220 is laid on the grid-less solar cell 200, and the film 220 tightly adheres the solder ribbon 130 to the surface of the cell, the peel strength of the film 220 can be tested at the corresponding stage. Peel strength reflects the coating pressure; better coating performance ensures better stability in the relative position between the solder ribbon 130 and the grid-less solar cell 200, thus avoiding solder ribbon misalignment and incomplete soldering problems during subsequent lamination processes. At the same stage, the pull-out strength of the solder ribbon 130 can also reflect the coating performance. For instance, a greater pull-out strength indicates better friction between the solder ribbon 130 and the film 220, and between the solder ribbon 130 and the grid-less solar cell 200, thereby ensuring better stability in the relative position between the solder ribbon 130 and the grid-less solar cell 200. After the lamination process, when the solder ribbon 130 and the gridless cell 200 have completed the corresponding stage of electrical interconnection, the peel strength test of the film 220 can be performed to ensure the adhesion performance of the gridless cell after lamination and to ensure the effectiveness of the electrical material bonding force of the gridless cell.

[0128] After the film 220 is subjected to a peel strength test, the corresponding peel strength value can be obtained. The judgment module 630 sets a standard value according to the stage state of the sample to be tested, and the coating performance of the sample to be tested can be reflected according to the relationship between the peel strength value and the standard value.

[0129] After performing a pull-out tensile test on the welding strip 130, the corresponding pull-out tensile value can be obtained. The judgment module 630 sets another standard value according to the stage state of the sample to be tested, and the coating performance of the sample to be tested can be reflected according to the relationship between the pull-out tensile value and the standard value.

[0130] In some embodiments, the judgment module 630 can use the peel tensile strength test result as the primary standard to judge the coating performance of the sample under test. For example, if only the peel tensile strength value meets the requirements, it can be said that the coating performance of the sample under test meets the requirements. It can also use the pull-out tensile strength test result as the primary standard to judge the coating performance of the sample under test. For example, if only the pull-out tensile strength value meets the requirements, it can be said that the coating performance of the sample under test meets the requirements. Alternatively, the peel tensile strength test result and the pull-out tensile strength test result can be used as a correlation standard to judge the coating performance of the sample under test. For example, if both the peel tensile strength value and the pull-out tensile strength value meet the standards, it can be said that the coating performance of the sample under test meets the requirements.

[0131] The coating performance testing device for grid-less solar cells provided in this embodiment of the invention acquires the sample to be tested through the acquisition module 610. Considering the structure of the sample itself, the testing module 620 can select to perform tensile performance testing on the thin film 220 and / or the solder ribbon 130 for the sample at different stages to reflect the coating performance of the sample. The judgment module 630 finally judges the coating performance of the sample based on the tensile performance test results. This realizes the coating performance testing for grid-less solar cell structures, which can effectively avoid the problems of solder ribbon misalignment and poor soldering in the subsequent lamination process of grid-less solar cells, and improve the production yield of grid-less solar cells.

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for testing the coating performance of a grid-less solar cell, characterized in that, include: Obtain the sample to be tested; the sample to be tested includes a grid-less solar cell, a thin film disposed on at least one side of the grid-less solar cell, and a solder strip sandwiched between the grid-less solar cell and the thin film; Based on the stage state of the sample to be tested, the film is subjected to a peel tensile strength test, and / or the solder strip is subjected to a pull-out tensile strength test; The coating performance of the sample under test is determined based on the tensile strength test results.

2. The method for testing the coating performance of grid-free solar cells according to claim 1, characterized in that, The stage states include a first state, which includes the state in which the thin film undergoes a cross-linking reaction to bond the solder ribbon to the gridless solar cell. Based on the stage state of the sample to be tested, tensile performance tests are performed on the film and / or the solder strip, including: When the sample to be tested is in the first state, the pull-out tensile strength test is performed on the solder strip, and / or, when the sample to be tested is in the first state, the peel tensile strength test is performed on the film.

3. The method for testing the coating performance of grid-free solar cells according to claim 2, characterized in that, When the sample to be tested is in the first state, the pull-out tensile strength test of the solder strip is performed, including: The sample to be tested is fixed; Clamp one end of the welding strip on the same side of the sample to be tested, and pull the welding strip away along the extension direction of the welding strip to obtain the pulling force of each welding strip.

4. The method for testing the coating performance of grid-free solar cells according to claim 3, characterized in that, When the sample to be tested is in the first state, the peel strength test of the film is performed, including: The sample to be tested is fixed; Clamp one side of the film in the sample to be tested, and peel the film along one side of the film in the direction of the opposite side of the film to obtain the peeling tensile force of the film.

5. The method for testing the coating performance of grid-free solar cells according to claim 4, characterized in that, The coating performance of the sample under test is obtained based on the tensile performance test results, including: The coating performance of the sample under test in the first state is determined based on the pull-out force of each of the solder strips; wherein, when the pull-out force of each of the solder strips is greater than the first preset force, it is determined that the sample under test meets the coating performance requirements in the first state. or, The coating performance of the sample under test in the first state is determined based on the peel strength of the film; wherein, when the peel strength of the film is greater than a second preset strength, the sample under test is determined to meet the coating performance requirements in the first state. or, The coating performance of the sample under test in the first state is determined based on the pull-out force of each solder strip and the peeling force of the film; wherein, when the pull-out force of each solder strip is greater than the first preset force and the peeling force of the film is greater than the second preset force, the sample under test is determined to meet the coating performance requirements in the first state.

6. The method for testing the coating performance of grid-free solar cells according to claim 2, characterized in that, The stage state includes a second state, which includes the state in which the thin film, the solder ribbon, and the grid-less solar cell have undergone a lamination process, and the solder ribbon and the grid-less solar cell are electrically interconnected. When the sample to be tested is in the first state, after performing a pull-out tensile strength test on the solder strip and / or a peel tensile strength test on the film, the method further includes: When the sample to be tested is in the second state, the peel strength performance test is performed on the film.

7. The method for testing the coating performance of grid-free solar cells according to claim 6, characterized in that, When the sample to be tested is in the second state, the peel strength test of the film is performed, including: The sample to be tested is fixed; A pre-cut layered strip extends inward from one side of the film, parallel to the extension direction of the solder strip, and the layered strip separates part of the gridless solar cell from the film; Clamp the layer strip and peel it off along one side of the film towards the opposite side of the film to obtain the peeling tensile force of the film.

8. The method for testing the coating performance of grid-free solar cells according to claim 7, characterized in that, Before fixing the sample to be tested, the following steps are included: The test sample is prepared by laminating the sample into a test laminate structure, which includes a glass substrate, a first transparent film, a second transparent film, and a back plate stacked together; the test sample is placed between the first transparent film and the second transparent film. The test stack structure also includes an isolation membrane, at least a portion of which is disposed between the thin film and the solder strip of the sample under test; A pre-cut layered strip extends inward from one side of the film, parallel to the extension direction of the solder ribbon. This layered strip separates a portion of the gridless solar cell from the film, including: The layered strip is cut from at least a portion of the separating film on one side surface of the backplate, wherein the backplate, the second transparent film, and the thin film adjacent to the second transparent film are cut simultaneously to form the layered strip.

9. The method for testing the coating performance of a gridless solar cell according to any one of claims 7-8, characterized in that, The coating performance of the sample under test is obtained based on the tensile performance test results, including: The coating performance of the sample under test in the second state is determined based on the peel strength of the film; wherein, when the sample under test meets the coating performance requirements in the first state and the peel strength of the film is greater than a third preset strength, it is determined that the sample under test meets the coating performance requirements.

10. A device for testing the coating performance of gridless solar cells, characterized in that, include: An acquisition module is used to acquire a sample to be tested; the sample to be tested includes a grid-less solar cell, a thin film disposed on one side of the grid-less solar cell, and a solder strip sandwiched between the grid-less solar cell and the thin film; The testing module is used to perform tensile performance testing on the film and / or the solder strip according to the stage state of the sample to be tested. The judgment module is used to judge the coating performance of the sample under test based on the test results of tensile performance.

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