Main-grid-free back contact battery assembly structure and preparation method thereof

Abstract

The invention belongs to the technical field of solar cells, and mainly relates to a main-grid-free back contact cell assembly structure and a preparation method thereof.The main-grid-free back contact cell assembly structure comprises a cell panel and a packaging assembly used for packaging the cell panel, and the cell panel comprises a plurality of cell strings arranged at intervals; each battery string comprises a plurality of battery pieces arranged at intervals, each battery string is provided with a plurality of welding strips and a plurality of adhesive tapes, and each adhesive tape adheres the corresponding welding strip to the corresponding battery piece, so that the welding strips are isolated from the packaging assembly; in any two adjacent welding strips, one welding strip is cut off at the odd number of battery pieces, and the other welding strip is cut off at the even number of battery pieces; and the welding strips at the front ends and the tail ends of the plurality of battery strings are respectively connected with bus bars to serve as positive lead ends and negative lead ends of the battery panel. The welding strip is not cut off when being laid, and is cut off after the adhesive tape is fixed, so that enough tension can be kept to be more easily aligned with a battery welding electrode.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cells, and mainly relates to a main grid-free back contact cell assembly structure and a preparation method thereof. Background Art

[0002] The existing busbar-free technology is to cut the thermal film into the size of the battery cell and glue it together with the circular welding strip to make a conductive strip, in which the thermal film is laid alternately on the upper and lower sides of the circular welding strip. Then the thermal film of the two composite welding strips is cut, and the battery is placed on the side with the welding strip but without the thermal film to heat press into a battery string.

[0003] The patent application document with application publication number CN117374165A discloses a method for preparing a busbar-less photovoltaic module, a busbar-less photovoltaic cell and a module. The method for preparing a busbar-less photovoltaic module and the busbar-less photovoltaic cell mention that adjacent cells are connected in sequence using welding ribbons, but this separate welding method may cause the originally placed cells to be misaligned after welding. Summary of the invention

[0004] The present invention provides a main grid-free back contact battery assembly structure and a preparation method thereof, so as to solve the problem of battery misalignment after welding in the prior art.

[0005] To solve the above problems, the present invention adopts the following technical solutions: A busbar-free back-contact battery assembly structure includes a battery panel and a packaging assembly for packaging the battery panel, wherein the battery panel includes a plurality of battery strings arranged at intervals, each battery string includes a plurality of battery slices arranged at intervals, and each battery string is provided with a plurality of welding strips and a plurality of adhesive tapes, each adhesive tape covers a corresponding welding strip, so that the corresponding welding strip is adhered to the battery slice, so that the welding strip is isolated from the packaging assembly; Of any two adjacent welding strips, one welding strip is cut at an odd number of battery cells, and the other welding strip is cut at an even number of battery cells, so that the same welding strip after cutting alternately serves as the positive electrode welding strip and the negative electrode welding strip of the corresponding battery cells; The welding strips at the front and end of the plurality of battery strings are respectively connected with bus bars to serve as the positive lead terminal and the negative lead terminal of the battery panel.

[0006] The invention has the following beneficial effects: the soldering tape is not cut when it is laid, and is cut after the adhesive tape is fixed, so that sufficient tension can be maintained and it is easier to align with the battery welding electrode; the traditional method uses solder paste welding or UV glue to fix the soldering tape, and the agglomerated solder balls or UV glue dots in the solder paste welding cause point-like protrusions on the surface of the battery cell, increasing the risk of hidden cracks; the invention ensures that the contact surface between the battery cell and the soldering tape is flat and free of point-like protrusions, thereby reducing the risk of hidden cracks and improving the yield.

[0007] Furthermore, a plurality of P grid lines and N grid lines are alternately arranged on the battery cell, the positive electrode welding strip is connected to the P grid line, and the negative electrode welding strip is connected to the N grid line.

[0008] The invention has the following beneficial effects: forming the positive and negative electrodes of the battery cell, and facilitating the extraction of the battery cell current.

[0009] Furthermore, there is a gap between two adjacent battery cells or they are overlapped with each other.

[0010] Furthermore, the width of the adhesive tape is 0.5 mm to 5 mm greater than the width of the welding tape.

[0011] Furthermore, the packaging assembly includes a front plate, a first packaging glue, a second packaging glue and a back plate / glass in sequence, and the battery panel is located between the first packaging glue and the second packaging glue.

[0012] The invention has the following beneficial effects: the packaging component and the solar panel are laminated to form a main grid-free back contact solar component structure, wherein after the welding tape is fixed by the adhesive tape, the welding tape is separated from the corresponding packaging adhesive, thereby preventing the packaging adhesive from flowing between the welding tape and the solar cell during the lamination process, causing poor contact and reducing the component power.

[0013] A method for preparing a busbar-free back contact battery assembly, comprising: Arrange multiple battery cells into battery strings as required; Placing multiple welding ribbons at welding positions of the battery string; Align the positions of the adhesive tape and the soldering tape and cover the soldering tape to stick the soldering tape on the battery cell; Of any two adjacent welding strips, one welding strip is cut at an odd number of cells, and the other welding strip is cut at an even number of cells; The front ends and the ends of the multiple battery strings are connected together to serve as the positive lead end and the negative lead end of the battery panel respectively, and then the battery panel is packaged.

[0014] The following beneficial effects are achieved: the soldering tape is not cut when it is laid, sufficient tension can be maintained to make it easier to align with the battery welding electrode, and the soldering tape is cut only after the adhesive tape is fixed.

[0015] Furthermore, a plurality of P grid lines and N grid lines are alternately arranged on the battery cell, welding strips are arranged on the P grid lines and the N grid lines, the positive electrode welding strip is connected to the P grid line, and the negative electrode welding strip is connected to the N grid line.

[0016] Furthermore, the width of the adhesive tape is 0.5 mm to 5 mm greater than the width of the welding tape.

[0017] The invention has the following beneficial effects: the packaging glue will not enter between the soldering ribbon and the battery cell.

[0018] Furthermore, the welding ribbon is cut using a laser or a mechanical cutter.

[0019] Furthermore, the adhesive tape is a heat-sensitive adhesive tape or a UV light-sensitive adhesive tape.

[0020] The invention has the following beneficial effects: the traditional method uses solder paste welding or UV glue to fix the solder strip. The agglomerated solder balls or UV glue dots in the solder paste welding cause point-like protrusions on the surface of the battery cell, increasing the risk of hidden cracks; the invention ensures that the contact surface between the battery cell and the solder strip is flat and free of point-like protrusions, thereby reducing the risk of hidden cracks and improving the yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein: Figure 1 A schematic diagram of the placement of battery cells; Figure 2 A schematic diagram of placing the solder ribbon on the battery cell; Figure 3 This is a schematic diagram of sticking the tape to the soldering tape; Figure 4 A schematic diagram for cutting the welding ribbon; Figure 5 It is a schematic diagram of the structure of a battery module without a main grid back contact; Figure 6 A schematic diagram of a combination of multiple busbar-free back-contact battery module structures; Figure 7 A top view of the solar panel.

[0022] Description of reference numerals: 1. Battery cell; 2. Solder ribbon; 3. Adhesive tape; 4. Front plate; 5. First packaging glue; 6. Second packaging glue; 7. Back plate; 8. Battery panel; 9. Bus bar; 10. P grid line; 11. N grid line. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Those skilled in the art should know that the embodiments described below are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0024] Various non-limiting embodiments of the present invention are described in detail below. Any number of elements in the accompanying drawings is for illustration and not for limitation, and any naming is only for distinction and does not have any limiting meaning. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0025] Embodiment of busbar-free back contact battery assembly structure like Figure 5 As shown, a busbar-free back-contact battery assembly structure includes a battery panel 8 and a packaging assembly for packaging the battery panel 8, the packaging assembly includes a front panel 4, a first packaging glue 5, a second packaging glue 6 and a back panel 7 in sequence, and the battery panel 8 is located between the first packaging glue 5 and the second packaging glue 6. The packaging assembly and the battery panel 8 constitute a busbar-free back-contact battery assembly structure. The combination of the packaging assembly and the battery panel 8 is completed by a lamination process. The front panel 4 and the back panel 7 in this embodiment can be any one of photovoltaic glass, TPT type panel, KPK type panel, KPF type panel, KPF type panel, TPE type panel or PPE type panel.

[0026] like Figure 3 As shown, the battery panel 8 includes a plurality of battery strings arranged at intervals (or evenly spaced), and these battery strings are located in the same plane. Each battery string includes a plurality of battery cells 1 arranged at intervals (or evenly spaced), and these battery cells 1 are also located in the same plane. A plurality of P grid lines 10 and N grid lines 11 are alternately arranged on each battery cell 1 in each battery string, and the P grid lines 10 and the N grid lines 11 are parallel to each other. At the same time, a plurality of welding strips 2 and a plurality of adhesive tapes 3 are arranged on the P grid lines 10 and the N grid lines 11. The welding strips 2 are in contact with the battery cell 1 through the P grid lines 10 and the N grid lines 11. The placement positions of the plurality of welding strips 2 completely overlap with the welding positions on the battery cell 1. The adhesive tape 3 is used to stick the corresponding welding strips 2 to the battery cell 1, and the welding strips 2 are used to connect a plurality of battery cells 1 in series. The extension direction of the welding strips 2 in this embodiment is perpendicular to the extension direction of the P grid lines 10 or the N grid lines 11.

[0027] In this embodiment, the plurality of welding strips 2 are arranged parallel to each other, and the welding strips 2 are arranged at intervals (or at equal intervals). The same welding strip 2 is located on multiple battery cells 1 at the same time, while the same P grid line 10 or N grid line 11 is only located on one battery cell 1. There is an interval between adjacent battery strings, and there is also an interval between adjacent battery cells 1.

[0028] In other embodiments, Figure 7 As shown, there is a negative spacing between two adjacent battery cells 1 on the same battery string, that is, the two battery cells 1 overlap at their edges, but the overlapping area is very small, and the battery cell 1 is very thin, which does not affect the adhesive tape 3 sticking the solder tape 2 to the battery cell 1.

[0029] In this embodiment, the width of the tape 3 is 0.5mm-5mm larger than the width of the soldering tape 2, for example, one of 0.5mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, and 5mm. The portion of the tape 3 that is wider than the soldering tape 2 will be pasted to the corresponding battery cell 1 to fix the soldering tape 2. The tape 3 can completely cover the soldering tape 2, ensuring that the soldering tape 2 will not contact the corresponding packaging glue, so that the packaging glue will not affect the welding effect. In addition, the traditional method uses solder paste welding or UV glue to fix the soldering tape. The agglomerated solder balls or UV glue dots in the solder paste welding form point-like protrusions on the surface of the battery cell 1, increasing the risk of hidden cracks; the present invention ensures that the contact surface between the battery cell 1 and the soldering tape is flat and free of point-like protrusions, reducing the risk of hidden cracks and improving the yield.

[0030] Each tape 3 covers the corresponding soldering tape 2, that is, one tape 3 covers a corresponding soldering tape 2, and the corresponding soldering tape 2 is pasted on the battery cell 1 by the tape 3, so that the soldering tape 2 can be isolated from the corresponding packaging glue. After the tape 3 fixes the soldering tape 2, the soldering tape 2 is separated from the corresponding packaging glue, which prevents the packaging glue from flowing between the soldering tape 2 and the battery cell 1 during the lamination process, causing poor contact and reducing the power of the component. At the same time, compared with laying the entire surface of the thermal film to cover the soldering tape 2, the use of the tape 3 reduces the use area of ​​the thermal film material and reduces the material cost. In addition, the soldering tape 2 is not cut during laying, so it can maintain sufficient tension and is easier to align with the battery welding electrode.

[0031] like Figure 4 As shown, among any two adjacent welding strips 2 on the same battery string, one welding strip 2 is cut off at an odd number of battery cells 1, and the other welding strip 2 is cut off at an even number of battery cells 1. After being cut, the same welding strip 2 is divided into multiple shorter welding strips 2, and these multiple shorter welding strips 2 are alternately used as positive welding strips and negative welding strips of the corresponding battery cells 1. In this embodiment, a laser or a mechanical cutter is used to cut the welding strip 2. The welding strip 2 is cut after the adhesive tape 3 is fixed. The positive welding strip is connected to the P grid line 10, and the negative welding strip is connected to the N grid line 11. At the same time, insulation treatment is performed between the positive welding strip and the N grid line 11, and between the negative welding strip and the P grid line 10 to prevent them from being turned on.

[0032] Compared with laying the entire surface of the thermal film to fix the welding tape 2, the use of the adhesive tape 3 reduces the use area of ​​the thermal film material and reduces the material cost; and the welding tape 2 is not cut when it is laid, so that sufficient tension can be maintained to make it easier to align with the battery welding electrode. The welding tape 2 is cut only after the adhesive tape 3 is fixed.

[0033] like Figure 5As shown, the welding strips 2 at the front and end of the multiple battery strings are respectively connected to the bus bars 9, that is, there are two bus bars 9, one bus bar 9 is connected to the welding strips 2 at the front ends of the multiple battery strings, and the other bus bar 9 is connected to the welding strips 2 at the ends of the multiple battery strings. These two bus bars 9 serve as the positive lead terminal and the negative lead terminal of the battery panel 8.

[0034] The adhesive tape 3 in this embodiment is a heat-sensitive adhesive tape. The battery string is heated as a whole, and the soldering tape 2 is quickly attached to the battery cell 1 through the heat-sensitive adhesive tape.

[0035] In other embodiments, the adhesive tape 3 is a UV photosensitive adhesive tape, which is irradiated with a UV light box to make it adhere quickly and form sufficient bonding force with the battery.

[0036] Example 1 of a method for preparing a busbar-free back contact battery assembly A method for preparing a busbar-free back contact battery assembly comprises the following steps: Step 1: If Figure 1 As shown, a plurality of battery cells 1 are arranged into a battery string as required, wherein each battery cell 1 has P gate lines 10 and N gate lines 11 arranged alternately in sequence, and the P gate lines 10 and the N gate lines 11 are parallel to each other.

[0037] Step 2: If Figure 2 As shown, the welding ribbon 2 is pulled and arranged on the P grid line 10 and the N grid line 11 , and a plurality of welding ribbons 2 are located at the welding position of the battery string.

[0038] Step 3: If Figure 3 As shown, the adhesive tape 3 is pulled to align the positions of the adhesive tape 3 and the welding tape 2, and the welding tape 2 is covered to paste the welding tape 2 on the battery cell 1. The width of the adhesive tape 3 is 0.5 mm larger than the width of the welding tape 2, and the part of the adhesive tape 3 that is larger than the welding tape 2 is pasted on the battery cell 1, thereby fixing the welding tape 2 on the battery cell 1. Since the welding tape 2 and the adhesive tape 3 used in the entire battery string are pulled and aligned at one time, the frequency of alignment is reduced, thereby reducing the risk of the welding tape 2 being offset.

[0039] The traditional method uses solder paste welding or UV glue to fix the solder strip. The agglomerated solder balls or UV glue dots in the solder paste welding cause point-like protrusions on the surface of the battery cell 1, increasing the risk of hidden cracks. The present invention ensures that the contact surface between the battery cell 1 and the solder strip is flat and free of point-like protrusions, thereby reducing the risk of hidden cracks and improving the yield.

[0040] Step 4: If Figure 4 As shown, after the soldering ribbon 2 is fixed, one of any two adjacent soldering ribbons 2 is cut at an odd number of cells 1, and the other soldering ribbon 2 is cut at an even number of cells 1. In this embodiment, the soldering ribbon 2 is cut using a laser or a mechanical cutter.

[0041] Step 5: If Figure 5 As shown, the front ends and the ends of the plurality of battery strings are connected together through two bus bars 9, respectively. The two bus bars 9 serve as the positive lead terminal and the negative lead terminal of the battery panel 8, respectively, and then the battery panel 8 is packaged.

[0042] The same welding ribbon 2 after being cut is divided into multiple shorter welding ribbons 2, and these multiple shorter welding ribbons 2 are alternately used as positive welding ribbons and negative welding ribbons of the corresponding battery cells 1. The positive welding ribbon is connected to the P grid line 10, and the negative welding ribbon is connected to the N grid line 11. At the same time, insulation treatment is performed between the positive welding ribbon and the N grid line 11, and between the negative welding ribbon and the P grid line 10 to prevent them from being turned on.

[0043] Figure 6 Schematic diagram of multiple busbar-free back-contact battery module structures combined together.

[0044] Compared with laying the entire surface of the thermal film to fix the welding tape 2, the use of the adhesive tape 3 reduces the use area of ​​the thermal film material and reduces the material cost; and the welding tape 2 is not cut when it is laid, so that sufficient tension can be maintained to make it easier to align with the battery welding electrode. The welding tape 2 is cut only after the adhesive tape 3 is fixed.

[0045] The distance between the battery cells 1 is determined according to the layout requirements. There may be a gap between the battery cells 1, or two battery cells 1 may overlap.

[0046] The adhesive tape 3 in this embodiment is a heat-sensitive adhesive tape. The battery string is heated as a whole, and the soldering tape 2 is quickly attached to the battery cell 1 through the heat-sensitive adhesive tape.

[0047] In other embodiments, the adhesive tape 3 is a UV photosensitive adhesive tape, which is irradiated with a UV light box to make it adhere quickly and form sufficient bonding force with the battery.

[0048] Example 2 of a method for preparing a busbar-free back contact battery assembly A method for preparing a busbar-free back contact battery assembly comprises the following steps: Step 1: If Figure 1 As shown, a plurality of battery cells 1 are arranged into a battery string as required, wherein each battery cell 1 has P gate lines 10 and N gate lines 11 arranged alternately in sequence, and the P gate lines 10 and the N gate lines 11 are parallel to each other.

[0049] Step 2: If Figure 2 As shown, the welding ribbon 2 is pulled and arranged on the P grid line 10 and the N grid line 11 , and a plurality of welding ribbons 2 are located at the welding position of the battery string.

[0050] Step 3: If Figure 3As shown, the adhesive tape 3 is pulled to align the position of the adhesive tape 3 with the welding tape 2, and the welding tape 2 is covered to paste the welding tape 2 on the battery cell 1. The width of the adhesive tape 3 is 1 mm larger than the width of the welding tape 2, and the part of the adhesive tape 3 that is larger than the welding tape 2 is pasted on the battery cell 1, thereby fixing the welding tape 2 on the battery cell 1. Since the welding tape 2 and the adhesive tape 3 used in the entire battery string are pulled and aligned at one time, the frequency of alignment is reduced, thereby reducing the risk of the welding tape 2 being offset.

[0051] The traditional method uses solder paste welding or UV glue to fix the solder strip. The agglomerated solder balls or UV glue dots in the solder paste welding cause point-like protrusions on the surface of the battery cell 1, increasing the risk of hidden cracks. The present invention ensures that the contact surface between the battery cell 1 and the solder strip is flat and free of point-like protrusions, thereby reducing the risk of hidden cracks and improving the yield.

[0052] Step 4: If Figure 4 As shown, after the soldering ribbon 2 is fixed, one of any two adjacent soldering ribbons 2 is cut at an odd number of cells 1, and the other soldering ribbon 2 is cut at an even number of cells 1. In this embodiment, the soldering ribbon 2 is cut using a laser or a mechanical cutter.

[0053] Step 5: If Figure 5 As shown, the front ends and the ends of the plurality of battery strings are connected together through two bus bars 9, respectively. The two bus bars 9 serve as the positive lead terminal and the negative lead terminal of the battery panel 8, respectively, and then the battery panel 8 is packaged.

[0054] Compared with laying the entire surface of the thermal film to fix the welding tape 2, the use of the adhesive tape 3 reduces the use area of ​​the thermal film material and reduces the material cost; and the welding tape 2 is not cut when it is laid, so that sufficient tension can be maintained to make it easier to align with the battery welding electrode. The welding tape 2 is cut only after the adhesive tape 3 is fixed.

[0055] The distance between the battery cells 1 is determined according to the layout requirements. There may be a gap between the battery cells 1, or two battery cells 1 may overlap.

[0056] Example 3 of the method for preparing a busbar-free back contact battery assembly A method for preparing a busbar-free back contact battery assembly comprises the following steps: Step 1: If Figure 1 As shown, a plurality of battery cells 1 are arranged into a battery string as required, wherein each battery cell 1 has P gate lines 10 and N gate lines 11 arranged alternately in sequence, and the P gate lines 10 and the N gate lines 11 are parallel to each other.

[0057] Step 2: If Figure 2 As shown, the welding ribbon 2 is pulled and arranged on the P grid line 10 and the N grid line 11 , and a plurality of welding ribbons 2 are located at the welding position of the battery string.

[0058] Step 3: If Figure 3 As shown, the adhesive tape 3 is pulled to align the position of the adhesive tape 3 with the welding tape 2, and the welding tape 2 is covered to paste the welding tape 2 on the battery cell 1. The width of the adhesive tape 3 is 2 mm larger than the width of the welding tape 2, and the part of the adhesive tape 3 that is larger than the welding tape 2 is pasted on the battery cell 1, thereby fixing the welding tape 2 on the battery cell 1. Since the welding tape 2 and the adhesive tape 3 used in the entire battery string are pulled and aligned at one time, the alignment frequency is reduced, thereby reducing the risk of the welding tape 2 being offset.

[0059] The traditional method uses solder paste welding or UV glue to fix the solder strip. The agglomerated solder balls or UV glue dots in the solder paste welding cause point-like protrusions on the surface of the battery cell 1, increasing the risk of hidden cracks. The present invention ensures that the contact surface between the battery cell 1 and the solder strip is flat and free of point-like protrusions, thereby reducing the risk of hidden cracks and improving the yield.

[0060] Step 4: If Figure 4 As shown, after the soldering ribbon 2 is fixed, one of any two adjacent soldering ribbons 2 is cut at an odd number of cells 1, and the other soldering ribbon 2 is cut at an even number of cells 1. In this embodiment, the soldering ribbon 2 is cut using a laser or a mechanical cutter.

[0061] Step 5: If Figure 5 As shown, the front ends and the ends of the plurality of battery strings are connected together through two bus bars 9, respectively. The two bus bars 9 serve as the positive lead terminal and the negative lead terminal of the battery panel 8, respectively, and then the battery panel 8 is packaged.

[0062] Compared with laying the entire surface of the thermal film to fix the welding tape 2, the use of the adhesive tape 3 reduces the use area of ​​the thermal film material and reduces the material cost; and the welding tape 2 is not cut when it is laid, so that sufficient tension can be maintained to make it easier to align with the battery welding electrode. The welding tape 2 is cut only after the adhesive tape 3 is fixed.

[0063] The distance between the battery cells 1 is determined according to the layout requirements. There may be a gap between the battery cells 1, or two battery cells 1 may overlap.

[0064] Example 4 of the method for preparing a busbar-free back contact battery assembly A method for preparing a busbar-free back contact battery assembly comprises the following steps: Step 1: If Figure 1 As shown, a plurality of battery cells 1 are arranged into a battery string as required, wherein each battery cell 1 has P gate lines 10 and N gate lines 11 arranged alternately in sequence, and the P gate lines 10 and the N gate lines 11 are parallel to each other.

[0065] Step 2: If Figure 2 As shown, the welding ribbon 2 is pulled and arranged on the P grid line 10 and the N grid line 11 , and a plurality of welding ribbons 2 are located at the welding position of the battery string.

[0066] Step 3: If Figure 3 As shown, the adhesive tape 3 is pulled to align the position of the adhesive tape 3 with the welding tape 2, and the welding tape 2 is covered to paste the welding tape 2 on the battery cell 1. The width of the adhesive tape 3 is 3 mm larger than the width of the welding tape 2, and the part of the adhesive tape 3 that is larger than the welding tape 2 is pasted on the battery cell 1, thereby fixing the welding tape 2 on the battery cell 1. Since the welding tape 2 and the adhesive tape 3 used in the entire battery string are pulled and aligned at one time, the alignment frequency is reduced, thereby reducing the risk of the welding tape 2 being offset.

[0067] The traditional method uses solder paste welding or UV glue to fix the solder strip. The agglomerated solder balls or UV glue dots in the solder paste welding cause point-like protrusions on the surface of the battery cell 1, increasing the risk of hidden cracks. The present invention ensures that the contact surface between the battery cell 1 and the solder strip is flat and free of point-like protrusions, thereby reducing the risk of hidden cracks and improving the yield.

[0068] Step 4: If Figure 4 As shown, after the soldering ribbon 2 is fixed, one of any two adjacent soldering ribbons 2 is cut at an odd number of cells 1, and the other soldering ribbon 2 is cut at an even number of cells 1. In this embodiment, the soldering ribbon 2 is cut using a laser or a mechanical cutter.

[0069] Step 5: If Figure 5 As shown, the front ends and the ends of the plurality of battery strings are connected together through two bus bars 9, respectively. The two bus bars 9 serve as the positive lead terminal and the negative lead terminal of the battery panel 8, respectively, and then the battery panel 8 is packaged.

[0070] Compared with laying the entire surface of the thermal film to fix the welding tape 2, the use of the adhesive tape 3 reduces the use area of ​​the thermal film material and reduces the material cost; and the welding tape 2 is not cut when it is laid, so that sufficient tension can be maintained to make it easier to align with the battery welding electrode. The welding tape 2 is cut only after the adhesive tape 3 is fixed.

[0071] The distance between the battery cells 1 is determined according to the layout requirements. There may be a gap between the battery cells 1, or two battery cells 1 may overlap.

[0072] Example 5 of the method for preparing a busbar-free back contact battery assembly A method for preparing a busbar-free back contact battery assembly comprises the following steps: Step 1: If Figure 1 As shown, a plurality of battery cells 1 are arranged into a battery string as required, wherein each battery cell 1 has P gate lines 10 and N gate lines 11 arranged alternately in sequence, and the P gate lines 10 and the N gate lines 11 are parallel to each other.

[0073] Step 2: If Figure 2As shown, the welding ribbon 2 is pulled and arranged on the P grid line 10 and the N grid line 11 , and a plurality of welding ribbons 2 are located at the welding position of the battery string.

[0074] Step 3: If Figure 3 As shown, the adhesive tape 3 is pulled to align the position of the adhesive tape 3 with the welding tape 2, and the welding tape 2 is covered to paste the welding tape 2 on the battery cell 1. Among them, the width of the adhesive tape 3 is 4mm larger than the width of the welding tape 2, and the part of the adhesive tape 3 that is larger than the welding tape 2 is pasted on the battery cell 1, so as to fix the welding tape 2 on the battery cell 1. Since the welding tape 2 and the adhesive tape 3 used in the entire battery string are pulled and aligned at one time, the frequency of alignment is reduced, thereby reducing the risk of the welding tape 2 being offset.

[0075] The traditional method uses solder paste welding or UV glue to fix the solder strip. The agglomerated solder balls or UV glue dots in the solder paste welding cause point-like protrusions on the surface of the battery cell 1, increasing the risk of hidden cracks. The present invention ensures that the contact surface between the battery cell 1 and the solder strip is flat and free of point-like protrusions, thereby reducing the risk of hidden cracks and improving the yield.

[0076] Step 4: If Figure 4 As shown, after the soldering ribbon 2 is fixed, one of any two adjacent soldering ribbons 2 is cut at an odd number of cells 1, and the other soldering ribbon 2 is cut at an even number of cells 1. In this embodiment, the soldering ribbon 2 is cut using a laser or a mechanical cutter.

[0077] Step 5: If Figure 5 As shown, the front ends and the ends of the plurality of battery strings are connected together through two bus bars 9, respectively. The two bus bars 9 serve as the positive lead terminal and the negative lead terminal of the battery panel 8, respectively, and then the battery panel 8 is packaged.

[0078] Compared with laying the entire surface of the thermal film to fix the welding tape 2, the use of the adhesive tape 3 reduces the use area of ​​the thermal film material and reduces the material cost; and the welding tape 2 is not cut when it is laid, so that sufficient tension can be maintained to make it easier to align with the battery welding electrode. The welding tape 2 is cut only after the adhesive tape 3 is fixed.

[0079] The distance between the battery cells 1 is determined according to the layout requirements. There may be a gap between the battery cells 1, or two battery cells 1 may overlap.

[0080] Example 6 of the method for preparing a busbar-free back contact battery assembly A method for preparing a busbar-free back contact battery assembly comprises the following steps: Step 1: If Figure 1 As shown, a plurality of battery cells 1 are arranged into a battery string as required, wherein each battery cell 1 has P gate lines 10 and N gate lines 11 arranged alternately in sequence, and the P gate lines 10 and the N gate lines 11 are parallel to each other.

[0081] Step 2: If Figure 2 As shown, the welding ribbon 2 is pulled and arranged on the P grid line 10 and the N grid line 11 , and a plurality of welding ribbons 2 are located at the welding position of the battery string.

[0082] Step 3: If Figure 3 As shown, the adhesive tape 3 is pulled to align the position of the adhesive tape 3 with the welding tape 2, and the welding tape 2 is covered to paste the welding tape 2 on the battery cell 1. The width of the adhesive tape 3 is 5 mm larger than the width of the welding tape 2, and the part of the adhesive tape 3 that is larger than the welding tape 2 is pasted on the battery cell 1, thereby fixing the welding tape 2 on the battery cell 1. Since the welding tape 2 and the adhesive tape 3 used in the entire battery string are pulled and aligned at one time, the alignment frequency is reduced, thereby reducing the risk of the welding tape 2 being offset.

[0083] The traditional method uses solder paste welding or UV glue to fix the solder strip. The agglomerated solder balls or UV glue dots in the solder paste welding cause point-like protrusions on the surface of the battery cell 1, increasing the risk of hidden cracks. The present invention ensures that the contact surface between the battery cell 1 and the solder strip is flat and free of point-like protrusions, thereby reducing the risk of hidden cracks and improving the yield.

[0084] Step 4: If Figure 4 As shown, after the soldering ribbon 2 is fixed, one of any two adjacent soldering ribbons 2 is cut at an odd number of cells 1, and the other soldering ribbon 2 is cut at an even number of cells 1. In this embodiment, the soldering ribbon 2 is cut using a laser or a mechanical cutter.

[0085] Step 5: If Figure 5 As shown, the front ends and the ends of the plurality of battery strings are connected together through two bus bars 9, respectively. The two bus bars 9 serve as the positive lead terminal and the negative lead terminal of the battery panel 8, respectively, and then the battery panel 8 is packaged.

[0086] Compared with laying the entire surface of the thermal film to fix the welding tape 2, the use of the adhesive tape 3 reduces the use area of ​​the thermal film material and reduces the material cost; and the welding tape 2 is not cut when it is laid, so that sufficient tension can be maintained to make it easier to align with the battery welding electrode. The welding tape 2 is cut only after the adhesive tape 3 is fixed.

[0087] The distance between the battery cells 1 is determined according to the layout requirements. There may be a gap between the battery cells 1, or two battery cells 1 may overlap.

Claims

1. A busbar-free back-contact battery assembly structure, comprising a battery panel and a packaging assembly for packaging the battery panel, wherein the battery panel comprises a plurality of battery strings arranged at intervals, each battery string comprises a plurality of battery cells arranged at intervals, characterized in that: Each battery string is provided with a plurality of welding strips and a plurality of adhesive tapes, and each adhesive tape covers a corresponding welding strip, so that the corresponding welding strip is adhered to the battery cell, so that the welding strip is isolated from the packaging component; Of any two adjacent welding strips, one welding strip is cut at an odd number of battery cells, and the other welding strip is cut at an even number of battery cells, so that the same welding strip after cutting alternately serves as the positive electrode welding strip and the negative electrode welding strip of the corresponding battery cells; The welding strips at the front and end of the plurality of battery strings are respectively connected with bus bars to serve as the positive lead terminal and the negative lead terminal of the battery panel.

2. A busbar-free back contact battery assembly structure according to claim 1, characterized in that: A plurality of P grid lines and N grid lines are alternately arranged on the battery cell, the positive electrode welding strip is connected to the P grid line, and the negative electrode welding strip is connected to the N grid line.

3. The busbar-free back contact battery assembly structure according to claim 2, characterized in that: There is a gap between two adjacent battery sheets or they are overlapped with each other.

4. A busbar-free back contact battery assembly structure according to claim 3, characterized in that: The width of the adhesive tape is 0.5 mm to 5 mm greater than the width of the welding tape.

5. A busbar-free back contact battery assembly structure according to any one of claims 1 to 4, characterized in that: The packaging assembly includes a front plate, a first packaging glue, a second packaging glue and a back plate in sequence, and the battery panel is located between the first packaging glue and the second packaging glue.

6. A method for preparing a busbar-free back contact battery assembly, characterized in that: include: Arrange multiple battery cells into battery strings as required; Placing multiple welding ribbons at welding positions of the battery string; Align the positions of the adhesive tape and the soldering tape and cover the soldering tape to stick the soldering tape on the battery cell; Of any two adjacent welding strips, one welding strip is cut at an odd number of cells, and the other welding strip is cut at an even number of cells; The front ends and the ends of the multiple battery strings are connected together to serve as the positive lead end and the negative lead end of the battery panel respectively, and then the battery panel is packaged.

7. The method for preparing a busbar-free back contact battery assembly according to claim 6, characterized in that: A plurality of P grid lines and N grid lines are alternately arranged on the battery cell, welding strips are arranged on the P grid lines and the N grid lines, the positive electrode welding strip is connected to the P grid line, and the negative electrode welding strip is connected to the N grid line.

8. The method for preparing a busbar-free back contact battery assembly according to claim 7, characterized in that: The width of the adhesive tape is 0.5 mm to 5 mm greater than the width of the welding tape.

9. The method for preparing a busbar-free back contact battery assembly according to claim 8, characterized in that: Use a laser or mechanical cutter to cut the solder ribbon.

10. The method for preparing a busbar-free back contact battery assembly according to claim 9, characterized in that: The adhesive tape is a heat-sensitive adhesive tape or a UV-sensitive adhesive tape.

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