Solder strip contact test method and solder strip contact test device

Abstract

The invention provides a solder strip contact test method and a solder strip contact test device. The solder strip contact method comprises the following steps that a to-be-tested device is provided, the to-be-tested device comprises a connecting electrode and a plurality of solder strips, the plurality of solder strips are arranged side by side at intervals, the connecting electrode is arranged between two adjacent solder strips, the connecting electrode is connected to the two adjacent solder strips, and a solder strip distance and a resistance value exist between the two solder strips; obtaining a plurality of different solder strip intervals and a plurality of corresponding resistance values; and performing linear fitting processing on the plurality of obtained solder strip distances and the plurality of resistance values, and judging whether the contact performance of the solder strip is qualified or not according to a linear relation obtained by fitting. According to the testing method, the difference of the contact resistance between the welding strip and the substrate can be accurately detected, so that whether pseudo soldering exists in the welding strip or not is judged.

Description

Technical Field

[0001] The present invention relates to the technical field of resistance testing, and in particular to a soldering ribbon contact testing method and a soldering ribbon contact testing device. Background Art

[0002] Solder ribbons are often used to electrically connect multiple semiconductor devices. For example, a photovoltaic module consists of multiple solar cells, connected by ribbons that are welded to the grid electrodes. The quality of the weld between the ribbon and the grid electrodes significantly impacts the fill factor and conversion efficiency of the photovoltaic module, so the weld quality must be evaluated after completion.

[0003] Traditionally, evaluating the quality of solder ribbon welding involves either electroluminescence testing or weld tension testing. Electroluminescence testing uses the principle of electroluminescence to detect internal defects in solar cells, detecting issues such as leaky and broken solder joints. Weld tension testing uses a tensile testing machine to measure the peeling force of the solder ribbon, indirectly indicating its quality. However, these methods lack sufficient accuracy to detect cold solder joints, making it difficult to accurately determine the contact quality between the solder ribbon and the gate electrode. Summary of the Invention

[0004] In view of this, in order to more accurately detect the contact resistance between the welding ribbon and the electrode, thereby ensuring the welding quality of the welding ribbon, it is necessary to provide a welding ribbon contact testing method.

[0005] According to some embodiments of the present invention, a method for testing solder ribbon contact is provided, comprising the following steps:

[0006] A device under test is provided, the device under test comprising a connecting electrode and a welding strip, wherein the welding strips are multiple and arranged in parallel and at intervals, the connecting electrode is arranged between two adjacent welding strips, and the connecting electrode is connected to the two adjacent welding strips, and there is a welding strip spacing and a resistance value between the two welding strips;

[0007] Obtaining a plurality of different solder strip spacings and corresponding plurality of resistance values; and,

[0008] A linear fitting process is performed on the obtained plurality of solder strip intervals and the obtained plurality of resistance values, and whether the contact performance of the solder strip is qualified is determined based on the linear relationship obtained by the fitting.

[0009] In some embodiments of the present invention, the plurality of solder strips include a fixed test strip and a plurality of optional test strips sequentially spaced apart on one side of the fixed test strip. The step of obtaining a plurality of different solder strip spacings and the corresponding plurality of resistance values ​​includes:

[0010] The solder strip spacing between the fixed test strip and each of the selected test strips is obtained, and the resistance value between the fixed test strip and each of the selected test strips is measured accordingly.

[0011] In some embodiments of the present invention, among the plurality of welding strips, the intervals between two adjacent welding strips are equal.

[0012] In some embodiments of the present invention, the device to be tested also includes a welding electrode and a substrate, the welding electrode is arranged on the substrate, the welding strip is arranged on the side of the welding electrode away from the substrate, the welding strip includes an electrode contact portion arranged on the substrate and a test connection portion located outside the edge of the substrate, and multiple test connection portions in multiple welding strips are arranged to protrude from the same side edge of the substrate.

[0013] In some embodiments of the present invention, the plurality of test connection portions have the same length.

[0014] In some embodiments of the present invention, there is a spacing area between two adjacent welding strips, and each spacing area is provided with a plurality of spaced connection electrodes, and the connection electrodes on the plurality of spacing areas are arranged in the same manner.

[0015] In some embodiments of the present invention, the number of the connecting electrodes on each of the spaced regions is greater than or equal to 50.

[0016] In some embodiments of the present invention, the step of judging whether the contact performance of the soldering strip is qualified according to the linear relationship obtained by fitting includes judging whether the contact performance of the soldering strip is qualified according to the correlation degree of the linear relationship.

[0017] In some embodiments of the present invention, when the correlation degree is above 0.999, it is determined that the contact performance of the soldering ribbon is qualified.

[0018] In some embodiments of the present invention, the step of judging whether the contact performance of the soldering ribbon is qualified according to the linear relationship obtained by fitting further includes:

[0019] Taking the intercept of the linear relationship of the device to be tested as a test intercept, and comparing the test intercept with a reference intercept to determine whether the contact performance of the soldering ribbon is qualified;

[0020] The reference intercept is obtained by providing a reference device having the same structure as the device to be tested and having no cold solder joint problem, obtaining the linear relationship of the reference device in the same manner as that of obtaining the linear relationship of the device to be tested, and using the intercept of the linear relationship of the reference device as the reference intercept.

[0021] In some embodiments of the present invention, when the test intercept is less than 10% of the reference intercept, the contact performance of the soldering ribbon is determined to be qualified.

[0022] Furthermore, the present invention also provides a soldering ribbon contact testing device, comprising:

[0023] An electrical connection mechanism, the electrical connection mechanism comprising a plurality of electrical connectors, the plurality of electrical connectors being respectively used to electrically connect to a plurality of solder strips in the device under test;

[0024] a resistance testing mechanism, wherein a measuring electrode of the resistance testing mechanism is movably connected to the electrical connector, and the resistance testing mechanism is used to measure the resistance value between the two welding strips;

[0025] A data processing mechanism is used to perform linear fitting on the plurality of resistance values ​​and the corresponding solder strip spacings between the solder strips, and obtain a linear relationship.

[0026] During actual research, the present invention discovered that for multiple parallel and spaced solder strips, when soldering is good, a good linear relationship exists between the spacing between the solder strips and the corresponding resistance value. This linear relationship is also closely related to soldering quality. Based on this, the present invention's solder strip contact testing method obtains multiple different solder strip spacings and corresponding multiple resistance values, performs a linear fitting process, and determines whether the solder strip's contact performance is qualified based on the linear relationship obtained after the fitting process. This testing method can relatively accurately detect the difference in contact resistance between the solder strip and the substrate, thereby determining whether the solder strip has a cold solder joint problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a top view of a device to be tested;

[0028] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure of the device under test along AA';

[0029] Figure 3 It is a structural schematic diagram of a welding ribbon contact testing device;

[0030] Figure 4 Schematic diagram of the straight line obtained after linear fitting of samples 1 to 5;

[0031] Figure 5 Schematic diagram of the straight line obtained after linear fitting of samples 6 to 10.

[0032] The reference numerals and their meanings are as follows:

[0033] 110, welding ribbon; 130, welding electrode; 120, connecting electrode; 140, battery substrate; 210, electrical connector; 220, resistance testing mechanism; 310, sample stage; 320, electrical connection stage. DETAILED DESCRIPTION

[0034] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items, and "more than" as used herein includes two or more items.

[0036] In the present invention, unless otherwise indicated, the sum of the parts of each component in the composition can be 100 parts by weight. Unless otherwise indicated, the basis for percentages (including weight percentages) in the present invention is the total weight of the composition. In addition, "wt%" herein means mass percentage, and "at%" means atomic percentage.

[0037] In this article, unless otherwise indicated, each reaction step may be carried out in the order in which it is presented, or may be carried out out of the order in which it is presented. For example, other steps may be included between each reaction step, and the order of the reaction steps may be appropriately reversed. This is something that can be determined by a skilled person based on conventional knowledge and experience. Preferably, the reaction methods described herein are carried out sequentially.

[0038] The present invention provides a soldering ribbon contact testing method, which includes the following steps.

[0039] A device to be tested is provided, which includes a connecting electrode and a welding strip. There are multiple welding strips, which are arranged in parallel and at intervals. The connecting electrode is arranged between two adjacent welding strips, and the connecting electrode is connected to the two adjacent welding strips. There is a welding strip spacing and a resistance value between the two welding strips.

[0040] Obtain multiple different solder strip spacings and corresponding multiple resistance values. And,

[0041] A linear fitting process is performed on the obtained multiple soldering strip spacings and multiple resistance values, and whether the contact performance of the soldering strip is qualified is judged based on the linear relationship obtained by the fitting.

[0042] During actual research, the present invention discovered that for multiple parallel and spaced solder strips, when soldering is good, there is a good linear relationship between the spacing between the solder strips and the corresponding resistance value. This linear relationship is also closely related to soldering quality. Based on this, the present invention's solder strip contact testing method obtains multiple different solder strip spacings and corresponding multiple resistance values, performs a linear fitting process, and determines whether the solder strip's contact performance is qualified based on the linear relationship obtained after the fitting process. This testing method can relatively accurately detect the difference in contact resistance between the solder strip and the substrate, thereby determining whether the solder strip has a cold solder joint problem.

[0043] Based on this, the present invention provides a soldering ribbon contact testing method, which includes steps S1 to S4.

[0044] Step S1: providing a device to be tested.

[0045] Reference Figure 1 As shown, Figure 1 A schematic diagram of a top view of a device to be tested, referring to Figure 1 As shown, in this embodiment, the device to be tested may include a connecting electrode 120 and a welding strip 110. There are multiple welding strips 110, and the multiple welding strips 110 are arranged in parallel and at intervals. The connecting electrode 120 is arranged between two adjacent welding strips 110, and the connecting electrode 120 is connected to the two adjacent welding strips 110.

[0046] In some examples of this embodiment, the device under test may be a solar cell.

[0047] Reference Figure 1 As shown, in some examples of this embodiment, the solar cell includes a soldering ribbon 110, a connecting electrode 120, a welding electrode 130, and a cell substrate 140. The welding electrode 130 can be disposed on the cell substrate 140, and the soldering ribbon 110 can be disposed on a side of the soldering electrode 130 away from the cell substrate 140. The soldering ribbon 110 can be welded to the soldering electrode 130. Furthermore, the connecting electrode 120 can be disposed between two adjacent soldering electrodes 130 and contact the two adjacent soldering electrodes 130. It can be understood that the connecting electrode 120 is indirectly connected to the two adjacent soldering ribbons 110 through the soldering electrodes 130.

[0048] In some examples of this embodiment, the connecting electrode 120 may be a fine grid electrode of the solar cell.

[0049] In some examples of this embodiment, the welding electrode 130 may be a main grid electrode or a fine grid electrode of the solar cell.

[0050] In some examples of this embodiment, the cell substrate 140 may include a transparent conductive film, and the welding electrode 130 and the connecting electrode 120 may be disposed in contact with the transparent conductive film. In other examples, the cell substrate 140 may also include a passivation film or an anti-reflection film, and the connecting electrode 120 may be disposed in contact with the passivation film or the anti-reflection film.

[0051] Reference Figure 1 As shown, in some examples of this embodiment, multiple welding electrodes 130 are arranged in parallel.

[0052] In some examples of this embodiment, the material of the welding electrode 130 may be metal. Further, the material of the welding electrode 130 may be selected from one or more of silver, copper, aluminum, and tin.

[0053] In some examples of this embodiment, the material of the connection electrode 120 may be metal. Further, the material of the connection electrode 120 may be selected from one or more of silver, copper, aluminum, and tin.

[0054] In some examples of this embodiment, the materials of the welding electrode 130 and the connecting electrode 120 may be the same.

[0055] In some examples of this embodiment, the welding electrode 130 and the connecting electrode 120 may be connected by sintering.

[0056] Reference Figure 1 As shown, in some examples of this embodiment, one or more connecting electrodes 120 may be provided between two adjacent welding strips 110. Furthermore, multiple connecting electrodes 120 may be provided between two adjacent welding electrodes 130.

[0057] Reference Figure 1 As shown, in some examples of this embodiment, the extension direction of the connecting electrode 120 intersects with the extension direction of the welding ribbon 110 .

[0058] Reference Figure 1 As shown, in some examples of this embodiment, the extending direction of the connecting electrode 120 is perpendicular to the extending direction of the welding ribbon 110 .

[0059] Reference Figure 1 As shown, in some examples of this embodiment, a spacing region is provided between two adjacent solder ribbons 110. Each spacing region is provided with a plurality of spaced connection electrodes 120. The connection electrodes 120 in the plurality of spacing regions are arranged in the same manner. The same arrangement means that the positions of the connection electrodes 120 in the spacing regions have translational symmetry. That is, after translation, the connection electrodes 120 in one spacing region can overlap with the positions of the connection electrodes 120 in another spacing region. This ensures that the resistance between the two adjacent solder ribbons 110 is the same.

[0060] In some examples of this embodiment, the number of connecting electrodes 120 on each spacing region may be greater than or equal to 50.

[0061] Reference Figure 1 As shown, in some examples of this embodiment, the welding strip 110 includes an electrode contact portion arranged on the battery substrate 140 and a test connection portion protruding from the battery substrate 140, wherein the electrode contact portion directly contacts the welding electrode 130, and the test connection portion can be left vacant to facilitate connection with an external test electrode.

[0062] In some examples of this embodiment, the lengths of the plurality of solder ribbons 110 are equal.

[0063] In some examples of this embodiment, the lengths of the multiple test connections in the multiple soldering ribbons 110 are the same. Setting the lengths of the test connections to be the same helps maintain the same length of the soldering ribbons 110 connected to the test circuit during testing, thereby making the resistance of the soldering ribbons 110 portions equal, thereby minimizing random errors during the testing process.

[0064] In some examples of this embodiment, the material of the soldering ribbon 110 may be selected from one or more of copper, tin, aluminum, and iron.

[0065] During the actual research process, the present invention found that for multiple parallel and spaced solder strips 110, when the soldering is good, there is a good linear relationship between the solder strip spacing between the solder strips 110 and the corresponding resistance value. And this linear relationship is closely related to the soldering quality. For ease of understanding, the following is based on Figure 1 The device under test is analyzed, and the present invention also provides Figure 2 , Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure of the device under test along AA'.

[0066] Reference Figure 2 As shown, welding electrodes 130 and battery substrates 140 are sequentially arranged below the welding ribbons 110, and the welding electrodes 130 are connected by connecting electrodes 120. When the two welding ribbons 110 are energized, it can be considered that the current first flows through the first welding ribbon 110, passes through the structure between the two welding ribbons 110, and then flows out of the second welding ribbon 110. Therefore, the resistance between the two welding ribbons 110 is the sum of the total resistance of the two welding ribbons 110, the contact resistance of the welding ribbons 110, and the resistance of the structure between the two welding ribbons 110. That is, the resistance R between the two welding ribbons 110 can be calculated by the following formula (1).

[0067] (1)

[0068] In formula (1), R s is the resistance value of a single solder strip 110, R c is the contact resistance of the solder ribbon 110, R sh is the resistance of the structure between the two solder ribbons 110 .

[0069] Further, refer to Figure 2 As shown, the structure between the two welding strips 110 includes two welding electrodes 130 and a structure located between the two welding electrodes 130. The two welding electrodes 130 are connected to the battery substrate 140 via the connecting electrode 120. The resistance of the battery substrate 140 is much greater than the resistance of the connecting electrode 120 and can be ignored. It is approximately considered that the current is only conducted through the connecting electrode 120. Then the current flows through the first welding electrode 130, the connecting electrode 120, and then flows through the second welding electrode 130. Similar to the calculation method of the resistance between the two welding strips 110 mentioned above, the resistance between the two welding electrodes 130 can be regarded as the sum of the total resistance of the two welding electrodes 130, the contact resistance between the welding electrode 130 and the connecting electrode 120, and the total resistance of the connecting electrode 120. In the actual device structure, the contact resistance between the welding electrode 130 and the connecting electrode 120 can be ignored. Therefore, R sh It can be calculated approximately according to formula (2).

[0070] (2)

[0071] Among them, R b is the resistance of a single welding electrode 130, R f is the resistance per unit length of the connecting electrode 120, L is the length of the connecting electrode 120, which can be considered as the spacing between the two welding strips 110. Usually, there can be multiple connecting electrodes 120, and multiple connecting electrodes 120 are connected in parallel to the welding electrode 130. With n being the number of connecting electrodes 120 between two welding electrodes 130, the total resistance of the connecting electrodes 120 is LR. f / n.

[0072] Therefore, for a device under test including a welding electrode 130 , a connecting electrode 120 and a welding ribbon 110 , the resistance between two welding ribbons 110 can be approximated by the following formula (3).

[0073] (3)

[0074] In the above formula (3), R s is the resistance of a single soldering ribbon 110, which is a constant value for a soldering ribbon 110 of a fixed length; R c is the contact resistance between the welding strip 110 and the welding electrode 130, which is a constant value; R bR represents the resistance of a single welding electrode 130, which is a constant value for a welding electrode 130 of a fixed length; f is the resistance of the connecting electrode 120 per unit length, which is a constant value; n is the number of connecting electrodes 120 between two welding strips 110, which is also a constant value. Therefore, according to formula (3), the resistance between two welding strips 110 is linearly related to the spacing between the two welding strips 110. If a welding strip 110 has a cold solder joint, it will cause some connecting electrodes 120 to be difficult to conduct or increase their resistance, and the resistance between the two welding strips 110 will increase, deviating from the original linear relationship. Based on this, it can be judged whether the contact between the welding strip 110 and the welding electrode 130 is qualified.

[0075] In actual research, the present invention first discovered a good linear relationship between the resistance and the spacing between the two soldering ribbons 110, and then made the above theoretical deduction. Due to certain neglected terms in the deduction process, the actual results may differ. However, it is understood that this does not affect the actual linear relationship between the resistance and the spacing between the two soldering ribbons 110.

[0076] Step S2: obtaining a plurality of different solder strip spacings and corresponding plurality of resistance values.

[0077] Reference Figure 1 As shown, there is a strip spacing and a resistance value between the two strips 110. The resistance value between the two strips 110 can be obtained by testing with an external test electrode. The strip spacing between the two strips 110 can also be easily measured using a ruler or other tool.

[0078] In some examples of this embodiment, the multiple solder strips 110 include a fixed test strip and a plurality of optional test strips spaced in sequence on one side of the fixed test strip, and the steps of obtaining a plurality of different solder strip spacings and corresponding multiple resistance values ​​include: obtaining the solder strip spacings between the fixed test strip and each optional test strip, and correspondingly measuring the resistance values ​​between the fixed test strip and each optional test strip.

[0079] In some examples of this embodiment, among the plurality of welding strips, the intervals between two adjacent welding strips are equal.

[0080] In this embodiment, the obtained solder strip spacing can be the absolute distance between the two solder strips 110, or a parameter that can represent the distance between the two solder strips 110. For example, in this embodiment, the order of the selected test strips relative to the fixed test strips can be used to represent the distance between the two solder strips 110. In other embodiments, the number of other selected test strips located between the selected test strips and the fixed test strips can also be used to represent the solder strip spacing between the two solder strips 110.

[0081] It is understood that a soldering strip spacing and a corresponding resistance value can be used as a set of parameters. In this embodiment, the number of obtained soldering strip spacings and corresponding resistance values ​​should be greater than or equal to 3. Furthermore, in some examples of this embodiment, the number of obtained soldering strip spacings and corresponding resistance values ​​can be greater than or equal to 5 to ensure a more accurate fitting result.

[0082] In step S3 , a linear fitting process is performed on the obtained plurality of solder strip spacings and resistance values, and whether the contact performance of the solder strip 110 is qualified is determined based on the linear relationship obtained by the fitting.

[0083] In some examples of this embodiment, when performing linear fitting processing, the solder strip spacing can be used as the horizontal coordinate and the resistance value can be used as the vertical coordinate, that is, the obtained linear relationship is the linear relationship between the resistance value between the solder strips 110 and the solder strip spacing.

[0084] According to the present invention, if there is a cold solder joint between two soldering ribbons 110, the measured resistance will be higher. However, the resistance between two soldering ribbons 110 without a cold solder joint in the middle will remain normal. For example, if a soldering ribbon 110 in the middle has a cold solder joint, the resistance value measured before the problematic soldering ribbon 110 will be normal, while the resistance value measured after the problematic soldering ribbon 110 will be abnormal. This will lead to a poor correlation between multiple resistance values ​​and multiple soldering ribbon spacings.

[0085] Therefore, in some examples of this embodiment, whether the welding of the device to be tested is qualified can be judged by the correlation degree of the linear relationship. 2 The value is used to characterize the degree of linear correlation between a set of data. 2 The closer the value is to 1, the higher the linear correlation of the data set is. 2 The greater the difference between the value and 1, the lower the linear correlation of the data set.

[0086] Furthermore, in some examples of this embodiment, when R 2 When the value is above 0.999, it can be determined that the contact performance of the soldering tape 110 of the device under test is qualified. 2 When the value is above 0.9991, it can be determined that the contact performance of the soldering tape 110 of the device under test is qualified. 2 When the value is above 0.9992, it can be determined that the contact performance of the soldering tape 110 of the device under test is qualified. 2 When the value is above 0.9995, it can be determined that the contact performance of the soldering ribbon 110 of the device under test is qualified.

[0087] In some examples of this embodiment, the intercept of the linear relationship can also be used to determine whether the welding of the device to be tested is qualified. The intercept is the intercept of the linear relationship on the coordinate axis where the resistance value is located. According to the relationship shown in formula (3), when the spacing between the welding strips is 0, the resistance value between the welding strips 110 is a constant term and includes the resistance value of the welding strip 110, the contact resistance of the welding strip 110, and the resistance value of the welding electrode 130. The contact resistance of the welding strip 110 without a cold solder joint problem should be a constant value. When a cold solder joint problem exists, the contact resistance of the welding strip 110 will be higher than the normal resistance value. Therefore, in the step of determining whether the welding of the device to be tested is qualified by the intercept of the linear relationship, the intercept of the linear relationship can be compared with the reference intercept to determine whether the welding strip 110 of the device to be tested has a cold solder joint problem.

[0088] In some examples of this embodiment, the reference intercept may be preset. The reference intercept is obtained by providing a reference device having the same structure as the device under test and without a solder joint problem, obtaining a linear relationship for the reference device in the same manner as the linear relationship for the device under test, and using the intercept of the linear relationship for the reference device as the reference intercept.

[0089] It is understood that when a device under test has a cold solder joint problem, the test intercept will be greater than the reference intercept. In some examples of this embodiment, when the test intercept is less than 10% greater than the reference intercept, the contact performance of the soldering ribbon 110 can be considered qualified. In some examples of this embodiment, when the test intercept is less than 8% greater than the reference intercept, the contact performance of the soldering ribbon 110 can be considered qualified. In some examples of this embodiment, when the test intercept is less than 5% greater than the reference intercept, the contact performance of the soldering ribbon 110 can be considered qualified.

[0090] In some examples of this embodiment, the correlation degree of the linear relationship of the device under test and the test intercept can be combined to determine whether the contact between the soldering ribbon 110 and the soldering electrode 130 is qualified, so as to further improve the accuracy of the judgment.

[0091] In some examples of this embodiment, a step of quantitatively determining the contact resistance may be further included, wherein the contact resistance is a difference between half of the test intercept and the overall resistance of the single solder ribbon 110 and the single main gate electrode 130 .

[0092] Through the method of steps S1 to S3 , it is possible to more accurately determine whether there is a cold solder joint between the soldering ribbon 110 and the soldering electrode 130 of the device under test by using the contact resistance.

[0093] Conventional battery luminescence and tension testing methods typically only determine contact between the soldering ribbon 110 and the welding electrode 130, but are difficult to detect for problems such as cold solder joints. Compared to conventional electroluminescence testing methods, the testing method of the present invention directly measures the contact resistance to determine the contact performance of the soldering ribbon 110. This testing method can effectively detect subtle changes in contact resistance, effectively determining whether the contact performance of the soldering ribbon 110 is acceptable, and thus accurately reflecting the soldering quality of the soldering ribbon 110.

[0094] Furthermore, the present invention also provides a soldering ribbon contact testing device. Figure 3 As shown, Figure 3 The figure is a schematic diagram of the structure of a soldering ribbon contact test device according to the present invention. The soldering ribbon contact test device includes an electrical connection mechanism, a resistance testing mechanism 220, and a data processing mechanism. The electrical connection mechanism includes a plurality of electrical connectors 210, each of which is used to electrically connect to a plurality of soldering ribbons 110 in the device under test; a resistance testing mechanism 220, wherein the measuring electrodes of the resistance testing mechanism 220 are movably connected to the electrical connectors 210 and the resistance testing mechanism 220 is used to measure the resistance value between two soldering ribbons 110; and a data processing mechanism, which is used to perform a linear fit on the plurality of resistance values ​​and the corresponding soldering ribbon spacings between the soldering ribbons 110, and to obtain a test line and its intercept.

[0095] Among them, multiple electrical connectors 210 are used to connect to Figure 1 The soldering ribbon 110 of the device under test is shown connected. During resistance testing, the two test electrodes of the resistance testing mechanism 220 can be directly connected to the electrical connector 210 for testing. As will be appreciated, if the two test electrodes of the resistance testing mechanism 220 are directly connected to the soldering ribbon 110, it is difficult to ensure the length of the soldering ribbon 110 connected to the test circuit, thereby causing large random errors. However, the provision of the electrical connector 210 helps ensure that the length of the soldering ribbon 110 connected to the test circuit is consistent, thereby improving the accuracy of the test results.

[0096] In some examples of this embodiment, multiple electrical connectors 210 may be arranged in parallel and spaced apart, corresponding to the positions of the multiple soldering ribbons 110. Furthermore, the electrical connector 210 may be a conductive clamp. In actual use, simply controlling the position of each soldering ribbon 110 inserted into the conductive clamp to ensure that the length of each soldering ribbon 110 connected to the test circuit is the same.

[0097] In some examples of this embodiment, the resistance testing mechanism 220 may be an electrochemical workstation or a resistance tester.

[0098] In some examples of this embodiment, the data processing mechanism may be a computer.

[0099] Reference Figure 3 As shown, in some examples of this embodiment, the solder ribbon contact testing device may further include a sample stage 310 and an electrical connection stage 320. The sample stage 310 is used to support the device to be tested, and the electrical connection stage 320 is provided on one side of the sample stage 310 and is used to support the electrical connection mechanism. The provision of the sample stage 310 and the electrical connection stage 320 can make the connection between the solder ribbon 110 and the electrical connector 210 more stable.

[0100] Example

[0101] A solar cell is provided as a device to be tested. The solar cell includes multiple solder strips and multiple soldering electrodes. The soldering electrodes are connected by multiple connecting electrodes. The solder strips protrude 10 mm from one side edge of the cell substrate in their extending direction. The multiple solder strips are numbered in sequence along their arrangement direction.

[0102] Use alligator clips as electrical connectors, align and connect all solder strips to multiple electrical connectors, adjust the contact points between each electrical connector and the solder strips, and ensure that the lengths of the tested sections of all solder strips are equal.

[0103] A resistance tester was used. The first test electrode of the resistance tester was fixedly contacted with the crocodile clip at the outermost edge to electrically connect to the No. 1 solder strip. The second test electrode was contacted with the other crocodile clips one by one in turn, and the number of the solder strip electrically connected to the second test electrode and the resistance value were recorded. The number of the solder strip connected to the second test electrode minus the number of the solder strip connected to the first test electrode was used to represent the solder strip spacing.

[0104] Use the solder strip number as the horizontal axis and the resistance value as the vertical axis to input the computer, draw a scatter plot and perform linear fitting, obtain the expression of the fitting line and R 2 value.

[0105] Experiment 1: 5 solar cells from the same batch were selected as samples, marked as sample 1 to sample 5, and tested in the same way as in Example 1. The fitted curve can be seen in Figure 4 .

[0106] Experiment 2: Five solar cells from another batch were selected as samples, namely samples 6 to 10, and tested in the same manner as in Example 1. The fitted curve can be seen in Figure 5 .

[0107] Figure 4 and Figure 5The horizontal axis in represents the difference between the number of the solder strip connected to the second test electrode and the number of the solder strip connected to the first test electrode, which represents the spacing between the two solder strips. The actual distance between the two solder strips is obtained by multiplying the difference by the spacing between the two adjacent solder strips.

[0108] Reference Figure 4 As shown in the experiment 1, there is an obvious linear relationship between the resistance value and the spacing of samples 1 to 5, which in turn proves the effectiveness of the test method of the present invention. In addition, the slope and intercept of the fitting line of samples 1 to 5 are basically the same, and the correlation degree R of the fitting line is 2 All reached above 0.9999, demonstrating a high degree of correlation, indicating that none of Samples 1 through 5 had any cold solder joint issues. Furthermore, the calculated resistance of the solder ribbon was 7.159 mΩ, while the intercept of the fitted line further calculated the contact resistance between the ribbon and the welding electrode to be approximately 9 ± 1 mΩ, which is on the same order of magnitude as the ribbon's resistance, demonstrating good solder joint quality.

[0109] Reference Figure 5 As shown in Figure 2, in Test 2, the slopes and intercepts of the fitted lines for Samples 7 to 10 are essentially the same, and the correlations between the fitted lines are all above 0.9995, which is extremely high, indicating that there are no cold solder joint issues in Samples 7 to 10. In contrast, the correlation between the fitted lines for Sample 6 is only 0.9908, significantly lower than that for Samples 7 to 10, and both the slope and intercept of Sample 6 are significantly different from those of Samples 7 to 10, indicating that there is a cold solder joint issue in Sample 6.

[0110] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0111] The above embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A soldering ribbon contact testing method, characterized in that: The steps include: A device under test is provided, the device under test comprising a connecting electrode and a welding strip, wherein the welding strips are multiple and arranged in parallel and at intervals, the connecting electrode is arranged between two adjacent welding strips, and the connecting electrode is connected to the two adjacent welding strips, and there is a welding strip spacing and a resistance value between the two welding strips; Obtaining a plurality of different solder strip spacings and a plurality of corresponding resistance values; as well as, A linear fitting process is performed on the obtained plurality of solder strip intervals and the obtained plurality of resistance values, and whether the contact performance of the solder strip is qualified is determined based on the linear relationship obtained by the fitting.

2. The soldering ribbon contact testing method according to claim 1, wherein: The plurality of solder strips include a fixed test strip and a plurality of optional test strips sequentially spaced apart on one side of the fixed test strip. The step of obtaining a plurality of different solder strip spacings and the corresponding plurality of resistance values ​​includes: The solder strip spacing between the fixed test strip and each of the selected test strips is obtained, and the resistance value between the fixed test strip and each of the selected test strips is measured accordingly.

3. The soldering ribbon contact testing method according to claim 2, wherein: Among the plurality of welding strips, the intervals between two adjacent welding strips are equal.

4. The soldering ribbon contact testing method according to claim 2, wherein: The device to be tested also includes a welding electrode and a substrate, the welding electrode is arranged on the substrate, the welding strip is arranged on the side of the welding electrode away from the substrate, the welding strip includes an electrode contact portion arranged on the substrate and a test connection portion located outside the edge of the substrate, and multiple test connection portions in multiple welding strips are arranged to protrude from the same side edge of the substrate.

5. The soldering ribbon contact testing method according to claim 4, wherein: The lengths of the plurality of test connection parts are the same.

6. The soldering ribbon contact testing method according to any one of claims 1 to 5, characterized in that: There is a spacing area between two adjacent welding strips, and each spacing area is provided with a plurality of spaced connection electrodes, and the connection electrodes on the plurality of spacing areas are arranged in the same manner.

7. The soldering ribbon contact testing method according to claim 6, wherein: The number of the connecting electrodes on each of the spacing regions is greater than or equal to 50.

8. The soldering ribbon contact testing method according to any one of claims 1 to 5 and 7, wherein: The step of judging whether the contact performance of the soldering strip is qualified according to the linear relationship obtained by fitting includes: judging whether the contact performance of the soldering strip is qualified according to the correlation degree of the linear relationship.

9. The soldering ribbon contact testing method according to claim 8, wherein: When the correlation degree is above 0.999, it is determined that the contact performance of the soldering strip is qualified.

10. The soldering ribbon contact testing method according to any one of claims 1 to 5, 7 and 9, characterized in that: The step of judging whether the contact performance of the soldering strip is qualified according to the linear relationship obtained by fitting also includes: Taking the intercept of the linear relationship of the device to be tested as a test intercept, and comparing the test intercept with a reference intercept to determine whether the contact performance of the soldering ribbon is qualified; The reference intercept is obtained by providing a reference device having the same structure as the device to be tested and having no cold solder joint problem, obtaining the linear relationship of the reference device in the same manner as that of obtaining the linear relationship of the device to be tested, and using the intercept of the linear relationship of the reference device as the reference intercept.

11. The soldering ribbon contact testing method according to claim 10, wherein: When the test intercept is less than 10% of the reference intercept, the contact performance of the soldering ribbon is determined to be qualified.

12. A soldering ribbon contact testing device, characterized in that: include: An electrical connection mechanism, the electrical connection mechanism comprising a plurality of electrical connectors, the plurality of electrical connectors being respectively used to electrically connect to a plurality of solder strips in the device under test; a resistance testing mechanism, wherein a measuring electrode of the resistance testing mechanism is movably connected to the electrical connector, and the resistance testing mechanism is used to measure the resistance value between the two welding strips; A data processing mechanism is used to perform linear fitting on the plurality of resistance values ​​and the corresponding solder strip spacings between the solder strips, and obtain a linear relationship.

Images