Padless ultra-fine busbar back contact battery, back contact battery module, and manufacturing method

Abstract

A padless ultra-fine busbar back contact battery, a back contact battery module, and a manufacturing method. The back contact battery comprises first finger lines (10), second finger lines (20), first busbar lines (11), second busbar lines (21), first insulating layers (13), and second insulating layers (23); the widths of each first busbar line (11) and each second busbar line (21) in an X-axis direction are each independently 10-100 μm; the first busbar lines (11) or the second busbar lines (21) respectively extend or are spaced apart from each other along the same axis perpendicular to the corresponding finger lines connected to the first busbar lines (11) or the second busbar lines (21), and when the first busbar lines (11) or the second busbar lines (21) are spaced apart from each other, the distance L between every two adjacent corresponding first busbar lines (11) or second busbar lines (21) in a Y-axis direction is 5-100 mm. The back contact battery has the characteristics of low silver consumption and high double-sided rate, the production yield of manufacturing a module from the back contact battery can be improved, and a high CTM value is ensured.

Description

Padless ultra-fine main grid back contact battery and back contact battery module and preparation method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202310861730X filed with the State Intellectual Property Office of China on July 14, 2023, entitled “Padless Ultra-Fine Main Grid Back Contact Cell and Back Contact Cell Module and Preparation Method,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure belongs to the technical field of back-contact batteries, and in particular relates to a padless ultra-fine main-grid back-contact battery and a back-contact battery module and a preparation method thereof. Background Art

[0004] A back-contact solar cell is a cell in which both the emitter and base contact electrodes are placed on the back side of the cell (non-light-receiving side or non-front side). The light-receiving side or front side of the cell is not blocked by any metal electrodes, which effectively increases the short-circuit current of the cell. At the same time, the back side can allow for wider metal grid lines to reduce the series resistance and thus increase the fill factor. Moreover, this type of cell with no obstruction on the front side not only has a high conversion efficiency, but also looks more beautiful. At the same time, components with full back electrodes are easier to assemble.

[0005] For back-contact solar cells, the electrode structure is the core technology of the cell. In existing back-contact solar cell electrode structures, solder pads are typically placed on the busbars. In the first structure, the busbars and their solder pads are distributed along the edges of the cell. In the second structure, the busbars and their solder pads are distributed in the non-edge areas of the cell. The busbar width is generally greater than 0.1mm or greater than 0.5mm, and the solder pad size is close to 1mm×1mm.

[0006] However, existing back-contact solar cell structures have the following problems: For the first structure, a) the conductivity requirements for the fine grid lines are very high, with the fine grid lines accounting for more than 80% of the area on the back of the cell, resulting in a low bifaciality rate; b) the copper grid electrode is very thick, seriously affecting the production capacity of copper grid electrode equipment; c) the copper grid process poses environmental pressures. For the second structure, d) the main grid lines and pads require a large amount of low-temperature silver paste, which is expensive; e) after high-temperature string soldering in the module manufacturing process, the cell deforms significantly and the welding tension between the solder ribbon and the main grid lines is insufficient, affecting the production yield of the cell manufacturing module.

[0007] Summary of the Invention

[0008] The purpose of the present invention is to overcome the defects of the prior art of back-contact solar cells, such as high silver consumption, large deformation after welding, low tensile force, and low production yield, and to provide a padless ultra-fine main grid back-contact cell and a back-contact cell module and a preparation method. The back-contact cell has the characteristics of low cost (low silver consumption) and high bifaciality. At the same time, when making the module, the connection between the soldering ribbon and the cell has a large tensile force and the cell deformation after connection is small. It can improve the production yield of the back-contact cell manufacturing module and ensure a higher CTM value.

[0009] In order to achieve the above-mentioned objectives, in the first aspect, the present disclosure provides a padless ultra-fine main grid back contact battery, comprising a first fine grid line and a second fine grid line alternately arranged along the Y-axis direction of the back side and both extending along the X-axis direction to collect currents of two different polarities of the battery cell, a first main grid line perpendicular to the first fine grid line, a second main grid line perpendicular to the second fine grid line, and a first insulating layer arranged between the first main grid line and the second fine grid line and respectively contacting each other along the Z-axis direction, a second insulating layer arranged between the second main grid line and the first fine grid line and respectively contacting each other, the first main grid line connecting at least two first fine grid lines and the at least one second main grid line connected thereto, A thin grid line is closest to the X-axis edge of the back surface, the second main grid line connects at least two second thin grid lines and at least one of the connected second thin grid lines is closest to the X-axis edge of the back surface, and no pads are set on the first main grid line and the second main grid line, and the widths of the first main grid line and the second main grid line in the X-axis direction are independently 10-100 μm; the first main grid line or the second main grid line is respectively extended or spaced along the same axis perpendicular to the corresponding thin grid line to which it is connected, and when spaced, the distance L between two adjacent corresponding main grid lines in the Y-axis direction is 5-100 mm, preferably 10-100 mm.

[0010] In some preferred embodiments, the first busbars and the second busbars are arranged in pairs and the pairs are at least located on two side areas of the back side of the solar cell in the X-axis direction and / or the Y-axis direction.

[0011] More preferably, the first main grid line is located on the Y-axis center axis of the first insulating layer in contact with it or on the side of the Y-axis center axis, and the second main grid line is located on the Y-axis center axis of the second insulating layer in contact with it or on the side of the Y-axis center axis.

[0012] Further preferably, the first busbar and / or the second busbar are respectively located on the Y-axis center axis of the corresponding insulating layer they are in contact with, and respectively extend from one end to the other end of the back side of the solar cell in the Y-axis direction.

[0013] In some preferred embodiments, the first main grid line includes a first edge main grid line close to the X-axis edge of the back surface, the second main grid line includes a second edge main grid line close to the X-axis edge of the back surface, the first edge main grid line and the second edge main grid line both include a pair of left main grid line and right main grid line, and the paired left main grid line and right main grid line are respectively arranged on both sides of the Y-axis center axis of the same corresponding insulating layer.

[0014] More preferably, the first main grid line also includes a first intermediate main grid line located in the middle of the Y axis on the back side, and the second main grid line also includes a second intermediate main grid line located in the middle of the Y axis on the back side. The first intermediate main grid line and the second intermediate main grid line are respectively located on the Y axis center axis of the corresponding insulating layer in contact with them, and along the Y axis direction, the distance L between adjacent corresponding edge main grid lines and corresponding intermediate main grid lines and / or between two adjacent corresponding intermediate main grid lines is 10-100 mm.

[0015] In some preferred embodiments, the thickness of the first main grid line and the second main grid line in the Z-axis direction is independently 5-30 μm; the first fine grid line and the second fine grid line each independently meet: the width in the Y-axis direction is 10-100 μm, and the thickness in the Z-axis direction is 5-20 μm; the second insulating layer and the first insulating layer each independently meet: the length in the X-axis direction is 1-5 mm, the width in the Y-axis direction is 150-900 μm, and the thickness in the Z-axis direction is 20-70 μm.

[0016] In some preferred embodiments, the number of corresponding fine grid lines connected to the first bus bar and the second bus bar respectively is 2-10, the first bus bar and the second bus bar are arranged in pairs, and each cell is provided with 2-20 pairs of corresponding bus bars.

[0017] In some preferred embodiments, the second insulating layer and the first insulating layer are alternately arranged along the Y-axis direction to form two adjacent columns, and corresponding main gate lines are provided on at least part of the corresponding insulating layers and are spaced apart along the X-axis direction of their corresponding fine gate lines.

[0018] In the second aspect, the present disclosure provides a back-contact battery module, comprising a plurality of battery cells arranged in series, wherein the battery cells are the padless ultra-fine main grid back-contact batteries described in the first aspect, and the back-contact battery module further comprises a plurality of solder strips and curing glue, wherein the solder strips are arranged above each insulating layer and the corresponding main grid line thereon in the Z-axis direction and extend along the Y-axis direction, the solder strips connect the plurality of battery cells in series, and the curing glue is located above the solder strip area corresponding to the corresponding main grid line in the Z-axis direction, and the Y-axis length of the curing glue is less than the Y-axis length of the corresponding main grid line thereunder.

[0019] In some preferred embodiments, on the same soldering strip, the curing adhesive is arranged at intervals along the Y-axis direction.

[0020] In some preferred embodiments, the difference between the Y-axis length of the cured adhesive and the Y-axis length of the corresponding busbar thereunder is ≥1 mm.

[0021] In some preferred embodiments, the length of the curing adhesive in the X-axis direction is greater than the length of the soldering ribbon in the X-axis direction.

[0022] In some preferred embodiments, the soldering strip is a copper strip with a low-melting-point solder coating coated on the outer surface, the width of the copper strip in the X-axis direction is 0.3-2 mm, the thickness of the copper strip in the Z-axis direction is 0.05-0.2 mm, and the melting point of the low-melting-point solder coating is lower than 155°C.

[0023] In a third aspect, the present disclosure provides a method for preparing a back-contact battery module, wherein the back-contact battery module is the back-contact battery module described in the second aspect, and the preparation method comprises the following steps:

[0024] S1. Arrange the cells in series and lay welding strips along the Y-axis of each insulating layer and the corresponding busbars on the insulating layer;

[0025] S2, then forming UV glue on the corresponding solder strip area of ​​each busbar line, and then curing it by UV irradiation to form a cured glue;

[0026] S3. The battery strings obtained in S2 are sequentially converged, coated with adhesive films, and the front and back plates are arranged and then laminated, and the welding strips are connected to the corresponding fine grid lines during the lamination.

[0027] In some preferred embodiments, the thickness of the UV glue in S2 is 5-100 μm, and the curing energy is 300-3000 mJ / cm 2 ; The lamination temperature described in S3 is higher than the melting point temperature of the solder strip.

[0028] In some preferred embodiments, the forming of UV glue in S2 is performed by dispensing or spraying. Beneficial effects:

[0029] Research has found that the current production of back-contact battery modules requires soldering ribbons. This deformation of the cell occurs after soldering the ribbons, requiring a significant welding force to secure the ribbons to the cell. This welding force is directly related to the silver paste area connected to the ribbon: the larger the silver paste area, the greater the welding force. To increase this welding force, current back-contact batteries typically incorporate a single, wide silver paste grid line and multiple, large silver paste pads. This significantly increases silver paste consumption and can cause cell deformation during pad soldering. In this regard, the padless ultra-fine main grid back contact battery disclosed in the present invention does not have a pad and does not require welding, thereby avoiding the deformation of the battery cell caused by welding in the prior art. When the module is subsequently formed, a curing glue can be used to achieve a fixed connection between the welding strip and the battery cell. There is no need to treat the welding strip at high temperature, thereby ensuring the production yield; and the width of each main grid line is very small, only 10-100μm (the main grid line width in the prior art is generally greater than 0.1mm), and when the corresponding main grid line intervals are set, the main grid line can be formed by segmented printing, thereby significantly reducing the silver paste consumption of the main grid line. And when the interval is set, the distance L between two adjacent corresponding main grid lines in the Y-axis direction is controlled to be 5-100mm. The distance L is appropriate, which can ensure the fixed connection between the welding strip and the battery cell while taking into account the lower silver paste consumption and subsequent curing glue consumption, thereby helping to improve the module production yield and reduce material costs. Under the same conditions, if L is too large or too small, it will lead to a decrease in the module production yield or an increase in material costs.

[0030] Preferably, when the spacing is set, the distance L between two adjacent corresponding main grid lines in the Y-axis direction is 10-100 mm, more preferably 30-90 mm, and more preferably 40-80 mm.

[0031] The back contact battery module disclosed in the present invention adopts a padless ultra-fine main grid back contact battery in combination with a soldering tape and a curing glue. The curing glue has excellent bonding strength, and the pasting process does not require high temperature, so the battery cell will not be deformed. At the same time, the Y-axis length of the curing glue is set to be less than the Y-axis length of the corresponding main grid line below it, so that even if the soldering tape in the area covered by the curing glue has poor contact with the corresponding main grid line and fine grid line, the soldering tape can have good contact with the corresponding main grid line in the area not covered by the curing glue after lamination. The current collected by the fine grid line in the area covered by the curing glue is conducted to the corresponding main grid line in the area not covered by the curing glue through the connected main grid line, and then is led out through the soldering tape. Under the same conditions, if there is a phenomenon of no main grid line connection in the area covered by the UV glue (that is, the coverage area of ​​the curing glue is ≥ the area of ​​the corresponding main grid line below it), the UV glue will penetrate into the back of the soldering tape, resulting in poor contact or even insulation between the soldering tape and the fine grid line, and the current of the corresponding fine grid line cannot be led out through the soldering tape, which will affect the component power and reduce the CTM value of the back contact battery module.

[0032] In the preparation method disclosed herein, the soldering ribbon is fixed with UV glue after laying and then UV cured. The soldering ribbon does not need to be cured at high temperature, so there is no problem of deformation of the cell after fixing the soldering ribbon. The soldering ribbon is connected to the cell through UV glue, which significantly increases the tension between the soldering ribbon and the cell, thereby improving the module production yield. Among them, the soldering ribbon disclosed herein (preferably low-temperature soldering ribbon or low-melting-point soldering ribbon, such as copper ribbon with a low-melting-point solder coating on the outer surface) is connected to the narrow main grid line only after high-temperature lamination. At this time, the soldering ribbon is unable to produce deformation under the clamping of the adhesive film, the front plate, and the back plate, so there is no problem of deformation of the cell after fixing the soldering ribbon. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0034] FIG1 is a schematic diagram of a back contact battery with a first electrode structure in the prior art;

[0035] FIG2 is a schematic diagram of a back contact battery with a second electrode structure in the prior art;

[0036] FIG3 is a schematic diagram of a back contact battery with a third electrode structure in the prior art;

[0037] FIG4 is a schematic diagram of a back contact battery with corresponding fine grid lines formed according to embodiment 1 of the present disclosure;

[0038] FIG5 is a schematic diagram of a back contact battery with a corresponding insulating ink layer formed in Example 1 of the present disclosure and a schematic diagram of a back contact battery with an electrode structure in Comparative Example 4;

[0039] FIG6 is a schematic diagram of a back-contact battery with corresponding busbars formed on the back side of the battery according to Example 1 of the present disclosure;

[0040] FIG7 is a schematic diagram of a back-contact battery with corresponding busbars formed on the back side of the battery according to Example 2 of the present disclosure;

[0041] FIG8 is a schematic diagram of a back-contact battery with corresponding busbars formed on the back side of the battery according to Example 3 of the present disclosure;

[0042] FIG9 is a schematic diagram of a back-contact battery with corresponding busbars formed on the back side of the battery according to Example 4 of the present disclosure;

[0043] FIG10 is a schematic diagram of a back-contact battery with corresponding busbars formed on the back side of the battery in Example 5 of the present disclosure;

[0044] FIG11 is a schematic diagram of laying welding ribbons when making module series welding using the back-contact battery of Example 1 of the present disclosure;

[0045] FIG12 is a schematic diagram of the present disclosure of Example 1, wherein the back contact battery is used to make a module for serial welding after the glue at both ends of the battery is cured;

[0046] FIG13 is a schematic diagram of the back contact battery module of Example 1 after serial welding and lamination, after which the welding ribbon is connected to the fine grid electrode.

[0047] Explanation of the reference numerals: 10, first thin grid line, 20, second thin grid line, 12, first soldering pad, 22, second soldering pad, 13, first insulating layer, 23, second insulating layer, 11, first main grid line, 21, second main grid line, 3, soldering strip, 14, first connection point, 24, second connection point, 4, UV glue. DETAILED DESCRIPTION

[0048] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. Among them, the terms "optional" and "optional" all mean that they may be included or not (or may be present or not).

[0049] In the present disclosure, the length refers to the dimension in the X-axis direction, the width refers to the dimension in the Y-axis direction, and the thickness refers to the dimension in the Z-axis direction.

[0050] The present disclosure provides a padless ultra-fine busbar back-contact battery, comprising a first and a second fine busbar, a first and a second busbar, and a second insulating layer and a first insulating layer. The first and second fine busbars are alternately arranged along the Y-axis direction of the back surface and are both extended along the X-axis direction. The first and second fine busbars are used to collect currents of two different polarities (opposite polarities) from a battery cell. The first busbar is perpendicular to the first fine busbar, and the second busbar is perpendicular to the second fine busbar. Along the Z-axis direction, the first insulating layer is disposed between the first and second busbars and contacts the first and second busbars, respectively. The second insulating layer is disposed between the second busbar and the first fine busbar and contacts the second busbar and the first fine busbar, respectively.

[0051] In the present disclosure, the first busbar is configured to connect at least two first fine grid lines, with at least one of the connected first fine grid lines being closest to the X-axis edge of the back surface; the second busbar is configured to connect at least two second fine grid lines, with at least one of the connected second fine grid lines being closest to the X-axis edge of the back surface, and no pads are provided on the first busbar or the second busbar. It should be noted that the connection herein refers to the contact between the corresponding busbar and the corresponding fine grid line to achieve current convergence.

[0052] The width of the first and second busbars in the X-axis direction of the present disclosure is independently 10-100 μm. The present disclosure can reduce the consumption of silver paste while increasing the tension under the condition of using smaller busbar widths, and achieve a higher module production yield and CTM value.

[0053] The first main grid line or the second main grid line of the present disclosure is respectively extended or spaced along the same axis perpendicular to the corresponding fine grid line to which it is connected, and the distance L between two adjacent corresponding main grid lines in the Y-axis direction when spaced is 5-100mm, preferably 10-100mm. The distance L of the present disclosure when spaced is appropriate, which can ensure a fixed connection between the welding strip and the battery cell while taking into account a lower amount of silver paste and subsequent curing glue, thereby helping to improve the module production yield and reduce material costs. Under the same conditions, if L is too large or too small, it will lead to a decrease in the module production yield or an increase in material costs.

[0054] It should be pointed out that, in the present disclosure, the first main grid line or the second main grid line is respectively extended or spaced along the same axis perpendicular to the corresponding fine grid line to which it is connected, which means that the first main grid line is extended or spaced along the same axis perpendicular to the corresponding fine grid line to which it is connected, and the second main grid line is extended or spaced along the same axis perpendicular to the corresponding fine grid line to which it is connected.

[0055] In some preferred embodiments, the first busbar and the second busbar are arranged in pairs and the paired pairs are at least located on both sides of the back of the cell in the X-axis direction and / or the Y-axis direction. It is understood that at least one pair of the first busbar and the second busbar is arranged on either side of the back of the cell in the X-axis direction and / or the Y-axis direction.

[0056] More preferably, the first busbar is located on the Y-axis center axis of the first insulating layer in contact with it or on the side of the Y-axis center axis, and the second busbar is located on the Y-axis center axis of the second insulating layer in contact with it or on the side of the Y-axis center axis. It is understandable that the same busbar can be located on the Y-axis center axis or on the side of the Y-axis center axis of the corresponding insulating layer, and different busbars can be partially located on the Y-axis center axis of the corresponding insulating layer and partially located on the side of the Y-axis center axis of the corresponding insulating layer.

[0057] Further preferably, the first busbar and / or the second busbar are respectively located on the Y-axis center axis of the corresponding insulating layer they are in contact with, and respectively extend from one end to the other end of the back side of the solar cell in the Y-axis direction.

[0058] In some preferred embodiments, the first main grid lines and the second main grid lines are spaced apart along the same axis perpendicular to the corresponding fine grid lines to which they are connected.

[0059] In some specific embodiments, the first and second busbars are spaced apart along the same axis perpendicular to the corresponding fine grid lines to which they are connected. The first busbar is located on the Y-axis center axis of the first insulating layer it contacts, and the second busbar is located on the Y-axis center axis of the second insulating layer it contacts. This preferred solution is more conducive to reducing silver paste consumption while also increasing tension, thereby achieving a higher module production yield and CTM value.

[0060] In some preferred embodiments, the first main grid line includes a first edge main grid line close to the X-axis edge of the back surface, the second main grid line includes a second edge main grid line close to the X-axis edge of the back surface, the first edge main grid line and the second edge main grid line both include a pair of left main grid line and right main grid line, and the paired left main grid line and right main grid line are respectively arranged on both sides of the Y-axis center axis of the same corresponding insulating layer.

[0061] More preferably, the first main grid line also includes a first intermediate main grid line located in the middle of the Y axis on the back side, and the second main grid line also includes a second intermediate main grid line located in the middle of the Y axis on the back side, and the first intermediate main grid line and the second intermediate main grid line are respectively located on the Y axis center axis of the corresponding insulating layer they are in contact with.

[0062] Further preferably, along the Y-axis direction, a distance L between adjacent corresponding edge bus bars and corresponding middle bus bars and / or between two adjacent corresponding middle bus bars is 10-100 mm.

[0063] In some preferred embodiments, the thickness of the first bus bar and the second bus bar in the Z-axis direction are independently 5-30 μm.

[0064] Preferably, the first fine gate line and the second fine gate line each independently meet the following requirements: a width in the Y-axis direction is 10-100 μm, and a thickness in the Z-axis direction is 5-20 μm.

[0065] Preferably, the second insulating layer and the first insulating layer independently meet the following requirements: a length in the X-axis direction of 1-5 mm, a width in the Y-axis direction of 150-900 μm, and a thickness in the Z-axis direction of 20-70 μm.

[0066] In some preferred embodiments, the number of corresponding fine grid lines connected to the first bus bar and the second bus bar respectively is 2-10, the first bus bar and the second bus bar are arranged in pairs, and each cell is provided with 2-20 pairs of corresponding bus bars.

[0067] In some preferred embodiments, the second insulating layers and the first insulating layers are alternately arranged along the Y-axis direction to form two adjacent columns, and corresponding main grid lines are provided on at least a portion of the corresponding insulating layers and are spaced apart along the X-axis direction of their corresponding fine grid lines. The second insulating layers and the first insulating layers are alternately arranged along the Y-axis direction to form two adjacent columns, which means that the second insulating layers form one column and the first insulating layers form another column, and adjacent second insulating layers and first insulating layers are arranged crosswise.

[0068] The preparation of each electrode structure in the present disclosure can refer to the existing methods as long as the above structure can be obtained, for example, it can be formed by printing or inkjet printing. Each fine grid line can be formed by printing silver paste or by electroplating copper grid lines.

[0069] In the present disclosure, each main grid line and each fine grid line may be made of silver paste or other types of conductive materials, such as silver-coated copper paste.

[0070] In the second aspect, the present disclosure provides a back-contact battery module, comprising a plurality of battery cells arranged in series, wherein the battery cells are the padless ultra-fine main grid back-contact batteries described in the first aspect, and the back-contact battery module further comprises a plurality of solder strips and curing glue, wherein the solder strips are arranged above each insulating layer and the corresponding main grid line thereon in the Z-axis direction and extend along the Y-axis direction, and the solder strips connect the plurality of battery cells in series.

[0071] The curing glue disclosed in the present invention is located above the Z-axis direction of the welding strip area corresponding to the corresponding main grid line. It can be understood that the curing glue is located above the welding strip. And the Y-axis length of the curing glue is less than the Y-axis length of the corresponding main grid line below it, so that even if the welding strip in the area covered by the curing glue has poor contact with the corresponding main grid line and fine grid line, then after lamination, the welding strip can have good contact with the corresponding main grid line in the area not covered by the curing glue. The current collected by the fine grid line in the area covered by the curing glue is conducted to the corresponding main grid line in the area not covered by the curing glue through the connected main grid line, and then is conducted through the welding strip, thereby ensuring the CTM value of the back contact battery module.

[0072] The method of connecting the battery cells in series described in the present invention can be carried out in accordance with the prior art. For example, adjacent battery cells are connected by welding strips arranged on the first main grid line or the second main grid line, and the welding strip used to connect the previous adjacent battery cell along the Y-axis direction is different from the corresponding main grid line of the welding strip used to connect the next adjacent battery cell.

[0073] In some preferred embodiments, on the same solder strip, the curing adhesive is spaced apart along the Y-axis. This preferred solution can evenly distribute the bonding force between the solder strip and the battery cell, thereby improving the module production yield.

[0074] In some preferred embodiments, the difference between the Y-axis length of the cured adhesive and the Y-axis length of the corresponding busbar thereunder is ≥1 mm.

[0075] Preferably, the difference between the Y-axis length of the cured adhesive and the Y-axis length of the corresponding busbar below it is 1-5 mm. This preferred solution can ensure the yield rate of the connection between the solder ribbon and the solar cell while minimizing the amount of silver paste used for the busbar, thereby further improving the module production yield rate and reducing the silver paste cost.

[0076] The curing adhesive disclosed in the present invention has an X-axis length greater than an X-axis length of the soldering ribbon, and can wrap the soldering ribbon and bond it to the surface of the battery cell.

[0077] In some preferred embodiments, the soldering tape is a copper tape with a low-melting-point solder coating coated on the outer surface, the width of the copper tape in the X-axis direction is 0.3-2 mm, and the thickness of the copper tape in the Z-axis direction is 0.05-0.2 mm.

[0078] In the present disclosure, preferably, the melting point of the low-melting-point welding coating is lower than 155°C, preferably 120-145°C.

[0079] The material of the low-melting-point solder coating disclosed in the present invention only needs to meet the above-mentioned low melting point, for example, it can be at least one of tin, bismuth, silver, and indium.

[0080] In a third aspect, the present disclosure provides a method for preparing a back-contact battery module, wherein the back-contact battery module is the back-contact battery module described in the second aspect, and the preparation method comprises the following steps:

[0081] S1. Arrange the cells in series and lay welding strips along the Y-axis of each insulating layer and the corresponding busbars on the insulating layer;

[0082] S2, then forming UV glue on the corresponding solder strip area of ​​each busbar line, and then curing it by UV irradiation to form a cured glue;

[0083] S3. The battery strings obtained in S2 are sequentially converged, coated with adhesive films, and the front and back plates are arranged and then laminated, and the welding strips are connected to the corresponding fine grid lines during the lamination.

[0084] In some preferred embodiments, the thickness of the UV glue in S2 is 5-100 μm, and the curing energy is 300-3000 mJ / cm 2 .

[0085] Preferably, the lamination temperature in S3 is higher than the melting point of the solder strip, and further preferably, the lamination temperature is 145-155°C.

[0086] In some preferred embodiments, the forming of UV glue in S2 is performed by dispensing or spraying.

[0087] The laying of the adhesive film, setting of the front plate and the back plate and then laminating as described in S3 are all conventional module manufacturing processes. It can be understood that the adhesive film is laid on the front and back of the battery string formed by connecting the battery cells in series, the front plate is set on the front of the battery string, and the back plate is set on the back of the battery string.

[0088] The lamination disclosed in the present invention can achieve connection between the welding strip and the corresponding first fine grid line and the second fine grid line respectively, and the connection points include: a first connection point between the welding strip and the first fine grid line, and a second connection point between the welding strip and the second fine grid line.

[0089] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present disclosure and are not to be construed as limiting the present disclosure.

[0090] Example 1

[0091] A padless ultra-fine multi-busbar back contact battery, the preparation method and structure of which are as follows:

[0092] S101, as shown in FIG4 , provides a back contact battery electrode structure for forming a fine gate electrode, including:

[0093] A first fine grid line 10 for collecting the first polarity of the battery cell;

[0094] Second fine grid lines 20 for collecting the second polarity of the cell, which are arranged alternately with the first fine grid lines 10;

[0095] The first polarity and the second polarity are opposite polarities. The fine grid lines are formed by printing silver paste. The width of the first fine grid lines 10 and the thickness of the second fine grid lines 20 are both 50 μm and 10 μm.

[0096] S102, as shown in FIG5, alternately forming insulating ink layers on the first fine grid lines 10 and the second fine grid lines 20, including:

[0097] A first insulating layer 13 for insulating the second polarity of the battery cell, which is multiple and forms a row;

[0098] A second insulating layer 23 of the first polarity for insulating the battery cells, which is multiple and forms another column;

[0099] The insulating ink layer is formed by printing. The length of the first insulating layer 13 and the second insulating layer 23 are 3 mm, the width is 500 μm, and the thickness is 30 μm.

[0100] S103, as shown in FIG6, forming silver paste busbars on the first fine grid lines 10 and the second fine grid lines 20 at both ends of the battery, the silver paste busbars comprising:

[0101] A first busbar 11 for connecting the first fine busbar 10 at the end of the cell;

[0102] A second busbar 21 for connecting the second fine busbar 20 at the end of the cell;

[0103] The silver paste busbars are formed by printing. The width of the first busbar 11 and the thickness of the second busbar 21 are both 50 μm and 10 μm. The busbars connect three first fine busbars 10 or three second fine busbars 20. The first busbars 11 and the second busbars 21 are formed in pairs, and each cell has four pairs of busbars.

[0104] Silver paste main grid lines are set at both ends of the battery cell and are located on the Y-axis center axis of the corresponding insulating ink layer they are in contact with. The silver paste main grid lines are respectively connected to the first fine grid line 10 and the second fine grid line 20 counted from the outermost edge of the battery cell. The distance L between adjacent corresponding main grid lines in the direction perpendicular to the corresponding fine grid lines is 80 mm.

[0105] The production method and structure of the padless ultra-fine multi-busbar back contact battery module are as follows:

[0106] S104. As shown in FIG11 , the battery cells are arranged in series, and soldering tape 3 is applied on the upper surface of each insulating ink layer of the battery cells. The soldering tape 3 is a copper tape coated with a low-melting-point solderable coating. The copper tape has a width of 0.8 mm in the X-axis direction and a thickness of 0.1 mm in the Z-axis direction. The melting point of the solderable coating is 120-145°C.

[0107] Adjacent battery cells are connected via the welding strips 3 provided on the first busbar 11 or the second busbar 21, and the corresponding busbar (the first busbar 11) of the welding strip 3 used to connect the previous adjacent battery cell along the Y-axis direction is different from the corresponding busbar (the second busbar 21) of the welding strip 3 used to connect the next adjacent battery cell.

[0108] S105, as shown in FIG12, UV glue 4 is formed on the corresponding solder strip 3 area of ​​each main grid line by dispensing, and then cured by UV irradiation to form a cured glue. The thickness of the UV glue 4 is 60 μm, and the UV curing energy is 1000 mJ / cm 2 .

[0109] The curing glue is located above the Z-axis direction of the welding strip 3 area corresponding to the corresponding main grid line. The Y-axis length of the curing glue is less than the Y-axis length of the corresponding main grid line below it. The difference between the Y-axis length of the curing glue and the Y-axis length of the corresponding main grid line below it is 2 mm. The X-axis length of the curing glue is greater than the X-axis length of the welding strip.

[0110] S106, the series-connected battery strings are converged in a conventional manner, and adhesive films and front and back plate materials are applied to the front and back sides of the battery cells, and then laminated. As shown in FIG13 , after lamination, the welding ribbons 3 are connected to the first fine grid lines 10 and the second fine grid lines 20, respectively. The connection points include:

[0111] A first connection point 14 between the soldering ribbon 3 and the first thin grid line 10;

[0112] A second connection point 24 between the welding ribbon 3 and the second thin grid line 20;

[0113] The lamination temperature is 155°C, and a module is formed after lamination.

[0114] Example 2

[0115] The difference from Example 1 is:

[0116] S103. As shown in FIG7 , a silver paste grid line is formed on each of the first and second fine grid lines 10 and 20 at both ends (i.e., the side regions) and in the middle region of the cell, serving as a pair of busbars. This forms three pairs of busbars along the Y-axis of the cell. Subsequently, UV adhesive 4 is simultaneously applied to the corresponding busbars in the middle region. The distance L between adjacent busbars along the Y-axis is 40 mm.

[0117] Example 3

[0118] The difference from Example 1 is:

[0119] S103, as shown in FIG8, two silver paste grid lines are formed on the first fine grid lines 10 and the second fine grid lines 20 at both ends of the battery cell as a pair of the same type of main grid lines, that is, there are two corresponding main grid lines of the same type and they are symmetrically arranged on both sides of the corresponding insulating ink layer in the same column.

[0120] Example 4

[0121] The difference from Example 1 is:

[0122] S103. As shown in FIG9 , the same type of busbars formed on the first and second fine grid lines 10, 20 at both ends of the cell are adjacent and symmetrically arranged on both sides of the corresponding insulating ink layer in the same column, for a total of four adjacent pairs of different types of busbars. A silver paste busbar is formed on the first and second fine grid lines 10, 20 in the middle region of the cell, and is paired with the silver paste busbar formed synchronously with the adjacent column, for a total of two busbars in a pair. In the Y-axis direction, the distance L between adjacent busbars is 40 mm.

[0123] Example 5

[0124] The difference from Example 1 is:

[0125] S103, as shown in FIG10, a silver paste grid line is formed on the first fine grid line 10 and the second fine grid line 20 on the back of the cell, which extends completely from one end of the cell in the Y-axis direction to the other end and is synchronously formed with the silver paste grid line of the adjacent column as a pair of silver paste main grid lines.

[0126] Example 6

[0127] The difference from Example 1 is:

[0128] Adjust the Y-axis length of the busbar so that the difference between the Y-axis length of the busbar and the Y-axis length of the cured adhesive above it is 6 mm.

[0129] Example 7

[0130] The difference from Example 1 is:

[0131] The length of the main grid lines in the Y-axis direction is adjusted so that the distance L between two adjacent corresponding main grid lines in the Y-axis direction is 5 mm.

[0132] Comparative Example 1

[0133] As shown in Figure 1, the first main grid line 11 / the second main grid line 21 and the first solder pad 12 / the second solder pad 22 of the opposite electrodes are respectively designed at the edges of both sides of the battery cell. The carriers need to be transferred from one side of the battery cell to the other side, and the length of the first fine grid line 10 / the second fine grid line 20 for collecting the carriers is very long. The long-distance transmission of carriers places very high demands on the conductivity of the fine grid lines. Taking the copper grid line with good conductivity as an example, the first fine grid line 10 / the second fine grid line 20 generally occupies more than 80% of the area on the back of the battery. At the same time, the thickness of the copper grid line needs to reach more than 30μm, which greatly reduces the double-sidedness of the battery and seriously affects the production capacity of the copper grid electrode equipment. In addition, the copper electroplating process is also under environmental pressure. When the module is subsequently made, the first solder pads 12 / the second solder pads 22 on both sides of the battery cell are alternately connected by soldering ribbons to form a battery string.

[0134] In summary, Comparative Example 1 has the following problems: a) It requires very high conductivity for the fine grid lines, with the grid lines occupying more than 80% of the battery backside area, resulting in a low bifaciality rate; b) The copper grid electrode is very thick, severely impacting the production capacity of the copper grid electrode equipment; and c) The copper grid process presents environmental pressures.

[0135] Comparative Example 2

[0136] As shown in Figure 2, after silver paste is printed to form the crossed first fine grid lines 10 / second fine grid lines 20 of opposite polarity, an alternating first insulating layer 13 / second insulating layer 23 is printed on the upper surface of the first fine grid lines 10 / second fine grid lines 20, and then silver paste is printed to form the first main grid lines 11 / second main grid lines 21 and the first soldering pads 12 / second soldering pads 22. The width of the first main grid lines 11 / second main grid lines 21 is greater than 0.1 mm, and the size of the first soldering pads 12 / second soldering pads 22 is close to 1 mm x 1 mm. The amount of silver paste consumed by the first main grid lines 11 / second main grid lines 21 and the first soldering pads 12 / second soldering pads 22 is similar to that consumed by the first fine grid lines 10 / second fine grid lines 20, requiring a large amount of expensive silver paste, thereby significantly increasing the cost of the electrodes.

[0137] The subsequent production of the module is carried out in accordance with the method of Example 1, except that the S105 soldering ribbon 3 is fixed to the soldering pad by high-temperature welding, and the corresponding temperature of the high-temperature welding is 170-270°C. When making the module, because the back-contact battery is single-sided, the soldering ribbon 3 has a large stress after cooling after high-temperature welding, which causes the battery cell to have a large deformation after welding. In addition, the welding tension between the soldering ribbon 3 and the silver paste main grid line during the battery cell string welding process is generally less than 1N. Problems such as the soldering ribbon 3 and the silver paste main grid line falling off are prone to occur in the process after string welding, thereby affecting the production yield of the battery cell manufacturing module.

[0138] In summary, Comparative Example 2 has the following problems: a. A large amount of low-temperature silver paste is required for the main grid lines and pads, and the material cost is expensive; b. After high-temperature string welding of the module, the battery cells are greatly deformed and the welding tension between the welding ribbon 3 and the main grid lines is insufficient, which affects the production yield of the battery cell manufacturing module.

[0139] Comparative Example 3

[0140] As shown in Figure 3, after printing silver paste to form the first fine grid lines 10 / second fine grid lines 20 of cross-arranged opposite electrodes, the first insulating layer 13 / second insulating layer 23 arranged alternately are printed on the upper surface of the first fine grid lines 10 / second fine grid lines 20, and then the silver paste is printed to form the entire very wide first main grid lines 11 / second main grid lines 21, wherein the width of the first main grid lines 11 / second main grid lines 21 is generally greater than 0.5 mm, and the silver paste consumption of the first main grid lines 11 / second main grid lines 21 is close to that of the first fine grid lines 10 / second fine grid lines 20, requiring a large amount of expensive silver paste, thereby greatly increasing the cost of the electrode.

[0141] The subsequent production of the module is carried out in accordance with the method of Example 1, except that the S105 soldering ribbon 3 is fixed to the main grid line by high-temperature welding, and the corresponding temperature of the high-temperature welding is 170-270°C. When making the module, because the back-contact battery is single-sided, the soldering ribbon 3 has a large stress after cooling after high-temperature welding, which causes the battery cell to have a large deformation after welding. In addition, the welding tension between the soldering ribbon 3 and the silver paste main grid line during the battery cell string welding process is generally less than 1N. Problems such as the soldering ribbon 3 and the silver paste main grid line falling off are prone to occur in the process after string welding, thereby affecting the production yield of the battery cell production module.

[0142] In summary, the following problems exist in Comparative Example 3: a. This comparative example is mainly based on the consideration of welding tension. After the welding of the welding ribbon, the battery cell will be deformed. After the battery cell is deformed, there is a risk of partial detachment of the welding ribbon and the main grid line. Therefore, the use of a whole wide main grid line can better avoid the risk of partial detachment of the welding ribbon and the main grid line after welding, and has no effect on the battery efficiency. However, a large amount of low-temperature silver paste is required for the main grid line and the welding pad, and the material cost is expensive; b. After the high-temperature string welding of the module, the battery cell is greatly deformed and the welding tension between the welding ribbon 3 and the main grid line is insufficient, which affects the production yield of the battery cell manufacturing module.

[0143] Comparative Example 4

[0144] As shown in Figure 5, after printing silver paste to form the first fine grid lines 10 / second fine grid lines 20 of opposite polarity electrodes arranged in a cross pattern, the first insulating layer 13 / second insulating layer 23 arranged alternately are printed on the upper surface of the first fine grid lines 10 / second fine grid lines 20, and then there is no need to print silver paste to form the main grid electrode. The first fine grid lines 10 and the second fine grid lines 20 on the back of the battery are arranged alternately and have opposite polarities, so each electrode grid is independent. The subsequent production of the module is carried out according to the method of Example 1. When the module is produced, when the soldering tape 3 is fixed with UV glue 4, the UV glue 4 will penetrate between the soldering tape 3 and the electrode fine grid lines, resulting in poor contact or even insulation between the soldering tape 3 and the electrode fine grid lines in the area where the UV glue 4 is applied, thereby greatly affecting the power of the component, thereby reducing the CTM value from the battery to the component.

[0145] In comparative example 4, the UV glue 4 can easily penetrate between the soldering ribbon 3 and the electrode fine grid lines, resulting in poor contact or even insulation in the area where the UV glue 4 is applied, thereby affecting the CTM value when the battery is manufactured into components.

[0146] Comparative Example 5

[0147] The difference from Example 1 is:

[0148] The length of the main grid lines in the Y-axis direction is adjusted so that the distance L between two adjacent corresponding main grid lines in the Y-axis direction is 150 mm.

[0149] Test Case

[0150] The above embodiments and comparative examples were subjected to various performance tests, and the performance index parameter data are shown in Table 1. CTM (Cell To Module) refers to the power ratio after the battery is made into a module; tension refers to the tension between the welding ribbon and the busbar.

[0151] Table 1

[0152] The above performance data demonstrates that, compared to the comparative examples, the back-contact battery disclosed herein offers low cost (low silver consumption) and a high bifaciality rate. Furthermore, during module fabrication, the solder ribbon and cell connection exhibits high tensile strength, resulting in minimal cell deformation after connection. This improves the production yield of back-contact battery modules while maintaining a high CTM value. However, prior art comparative examples 1-3, comparative example 4, and comparative example 5, which fall outside the scope of this disclosure, exhibit unsuitable electrode structures or key parameters, resulting in overall performance inferior to that of the present disclosure.

[0153] Furthermore, according to Examples 1 and 2 of the present disclosure, it can be seen that by adopting the embodiment 2 of the preferred main grid structure of the present disclosure, although the silver paste consumption is slightly increased, the production yield can be further improved.

[0154] Furthermore, according to Example 1 and Examples 3-4 of the present disclosure, it can be seen that the use of Example 1 of the preferred main grid structure of the present disclosure is more conducive to reducing the consumption of silver paste while improving the CTM value.

[0155] Furthermore, according to Examples 1 and 5 of the present disclosure, it can be seen that the use of Example 1 of the preferred main grid structure of the present disclosure is more conducive to significantly reducing the consumption of silver paste while ensuring a higher module production yield.

[0156] Furthermore, according to Example 1 and Examples 6-7 of the present disclosure, it can be seen that adopting the preferred embodiment 1 of the present disclosure is more conducive to reducing the consumption of silver paste while ensuring the performance of the battery and its module.

[0157] The preferred embodiments of the present disclosure are described in detail above, but the present disclosure is not limited thereto. Within the technical concept of the present disclosure, various simple variations of the technical solution of the present disclosure may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed by the present disclosure and fall within the scope of protection of the present disclosure. Industrial Applicability

[0158] The present disclosure provides a padless ultra-fine main grid back contact battery and a back contact battery module and a preparation method, wherein the back contact battery comprises a first fine grid line and a second fine grid line, a first main grid line, a second main grid line, and a first insulating layer, a second insulating layer, wherein the width of the first main grid line and the second main grid line in the X-axis direction is independently 10-100 μm; the first main grid line or the second main grid line is respectively extended or spaced along the same axis perpendicular to the corresponding fine grid line to which it is connected, and when spaced, the distance L between two adjacent corresponding main grid lines in the Y-axis direction is 5-100 mm. The back contact battery disclosed in the present disclosure has the characteristics of low silver consumption and high bifaciality, which can improve the production yield of the back contact battery manufacturing module while ensuring a high CTM value.

[0159] Furthermore, it is understood that the disclosed padless ultra-fine busbar back-contact cells and back-contact cell modules and their preparation methods are reproducible and can be used in a variety of industrial applications. For example, the disclosed padless ultra-fine busbar back-contact cells and back-contact cell modules and their preparation methods can be used in the field of back-contact cell technology.

Claims

1. A padless ultra-fine main grid back contact battery, comprising first fine grid lines and second fine grid lines alternately arranged along the Y-axis direction of the back side and both extending along the X-axis direction to collect currents of two different polarities of the battery sheet, a first main grid line perpendicular to the first fine grid line, a second main grid line perpendicular to the second fine grid line, and a first insulating layer arranged between and in contact with the first main grid line and the second fine grid line along the Z-axis direction, and a second insulating layer arranged between and in contact with the second main grid line and the first fine grid line, characterized in that: The first main grid line connects at least two first fine grid lines and at least one of the first fine grid lines connected is closest to the X-axis edge of the back side, the second main grid line connects at least two second fine grid lines and at least one of the second fine grid lines connected is closest to the X-axis edge of the back side, and no pads are set on the first main grid line and the second main grid line, and the widths of the first main grid line and the second main grid line in the X-axis direction are independently 10-100μm; the first main grid line or the second main grid line is respectively extended or spaced along the same axis perpendicular to the corresponding fine grid line connected thereto, and when spaced, the distance L between two adjacent corresponding main grid lines in the Y-axis direction is 5-100mm.

2. The padless ultra-fine main grid back contact battery according to claim 1, characterized in that: The first busbars and the second busbars are arranged in pairs and the pairs are at least located at two side regions of the back side of the solar cell in the X-axis direction and / or the Y-axis direction.

3. The padless ultra-fine main grid back contact battery according to claim 2, characterized in that: The first main grid line is located on the Y-axis center axis of the first insulating layer in contact or on the side of the Y-axis center axis, and the second main grid line is located on the Y-axis center axis of the second insulating layer in contact or on the side of the Y-axis center axis.

4. The padless ultra-fine main grid back contact battery according to claim 3, characterized in that: The first busbar and / or the second busbar are respectively located on the Y-axis center axis of the corresponding insulating layer in contact, and extend from one end to the other end of the back side of the battery cell in the Y-axis direction.

5. The padless ultra-fine main grid back contact battery according to claim 1, characterized in that: The first main grid line includes a first edge main grid line close to the X-axis edge of the back side, the second main grid line includes a second edge main grid line close to the X-axis edge of the back side, the first edge main grid line and the second edge main grid line both include a pair of left main grid lines and right main grid lines, and the pairs of left main grid lines and right main grid lines are respectively arranged on both sides of the Y-axis center axis of the same corresponding insulating layer.

6. The padless ultra-fine main grid back contact battery according to claim 5, characterized in that: The first main grid line also includes a first intermediate main grid line located in the middle of the Y-axis on the back side, and the second main grid line also includes a second intermediate main grid line located in the middle of the Y-axis on the back side. The first intermediate main grid line and the second intermediate main grid line are respectively located on the Y-axis center axis of the corresponding insulating layer in contact, and along the Y-axis direction, the distance L between adjacent corresponding edge main grid lines and corresponding intermediate main grid lines and / or between two adjacent corresponding intermediate main grid lines is 10-100mm.

7. The padless ultra-fine main grid back contact battery according to claim 1, characterized in that: The thickness of the first main grid line and the second main grid line in the Z-axis direction is independently 5-30μm; the first fine grid line and the second fine grid line each independently satisfy: the width in the Y-axis direction is 10-100μm, and the thickness in the Z-axis direction is 5-20μm; the second insulating layer and the first insulating layer each independently satisfy: the length in the X-axis direction is 1-5mm, the width in the Y-axis direction is 150-900μm, and the thickness in the Z-axis direction is 20-70μm.

8. The padless ultra-fine main grid back contact battery according to claim 1, characterized in that: The number of corresponding fine grid lines connected to the first main grid line and the second main grid line is 2-10, the first main grid line and the second main grid line are arranged in pairs, and each cell is provided with 2-20 pairs of corresponding main grid lines; and / or The second insulating layers and the first insulating layers are alternately arranged along the Y-axis direction to form two adjacent columns, and corresponding main grid lines are arranged on at least part of the corresponding insulating layers and are spaced apart along the X-axis direction of their corresponding fine grid lines.

9. A back contact battery module, comprising a plurality of battery cells arranged in series, characterized in that: The battery cell is a padless ultra-fine main grid back contact battery as described in any one of claims 1-8, and the back contact battery module also includes a plurality of welding strips and curing glue, the welding strips are arranged above each insulating layer and the corresponding main grid line thereon in the Z-axis direction and extend along the Y-axis direction, the welding strips connect a plurality of battery cells in series, the curing glue is located above the welding strip area corresponding to the corresponding main grid line in the Z-axis direction, and the Y-axis length of the curing glue is less than the Y-axis length of the corresponding main grid line thereunder.

10. The back contact battery module according to claim 9, characterized in that: On the same solder strip, the curing glue is arranged at intervals along the Y-axis direction, and the length of the curing glue in the X-axis direction is greater than the length of the solder strip in the X-axis direction; and / or The difference between the length of the curing glue in the Y-axis direction and the length of the corresponding main grid line thereunder in the Y-axis direction is ≥1 mm.

11. The back contact battery module according to claim 9, characterized in that: The soldering strip is a copper strip with a low-melting-point solder coating coated on the outer surface. The width of the copper strip in the X-axis direction is 0.3-2 mm, and the thickness of the copper strip in the Z-axis direction is 0.05-0.2 mm. The melting point of the low-melting-point solder coating is lower than 155°C.

12. A method for preparing a back contact battery module, characterized in that: The back contact battery module is a back contact battery module as claimed in any one of claims 9 to 11, and the preparation method comprises the following steps: S1. Arrange the cells in series and lay welding strips on each insulating layer arranged along the Y-axis direction of the cells and on the corresponding main grid lines on the insulating layers; S2, then forming UV glue on the corresponding solder strip area of ​​each main grid line, and then curing it by UV irradiation to form a cured glue; S3, the battery strings obtained in S2 are successively converged, adhesive films are laid, front plates and back plates are arranged, and then laminated, and the lamination connects the welding strips with the corresponding fine grid lines.

13. The preparation method according to claim 12, characterized in that: The thickness of the UV glue in S2 is 5-100 μm, and the curing energy is 300-3000 mJ / cm 2 ; The lamination temperature in S3 is higher than the melting point of the solder strip; and / or The formation of UV glue in S2 is performed by dispensing or spraying.

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