Cell string welding method and string welding machine

Abstract

To provide a cell string welding method for suppressing PV ribbon welding deviation in a field of photovoltaic power.SOLUTION: A cell string welding method includes the steps of: detecting a battery cell set in which a plurality of battery cells are arranged, and in the case of failure, perform adjustment; cutting an initial PV ribbon to form a PV ribbon, setting, as a first position, a cutting position of an odd-numbered initial PV ribbon counted from one side along a first direction, and setting, as a second position, a cutting position of an even-numbered initial PV ribbon counted from one side of the initial PV ribbons along the first direction; controlling each of the PV ribbons to move along a second direction so that two PV ribbons adjacent to each other in a second direction have a pitch, and forming a PV ribbon set; transferring the PV ribbon set to the battery cell set; and welding the PV ribbon to a corresponding battery cell in the battery cell set so as to form a cell string.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to the field of photovoltaics, and more particularly to a method and string welder for welding cell strings. [Background technology]

[0002] An interdigitated back contact (IBC) solar cell is a back-contact solar cell structure in which positive and negative metal electrodes are arranged in a comb shape on the backlight surface of the cell, and the PN junction and electrodes are located on the back surface of the cell. In other words, the electrodes of the emitter and base regions of an IBC cell are both on the back surface, and there is no obstruction by grid lines on the front surface, which can improve the photoelectric conversion performance of the cell.

[0003] The method of welding IBC cell strings in series is to place the battery cells one after the other with their back sides facing up, and reverse the polarity of adjacent battery cells. A cell string is obtained by welding an alternating PV ribbon set with multiple battery cells. However, the PV ribbons in the alternating PV ribbon set are highly likely to bend, and the PV ribbons are very prone to deformation, which will ultimately lead to welding misalignment. Summary of the Invention [Problem to be solved by the invention]

[0004] The embodiments of the present disclosure provide a cell string welding method and string welder that are advantageous in at least solving the problem of PV ribbon bending and welding misalignment. [Means for solving the problem]

[0005] According to some embodiments of the present disclosure, one aspect of the embodiment of the present disclosure provides a method for welding a cell string, the method for welding a cell string includes providing a plurality of battery cells, arranging the plurality of battery cells to form a battery cell set, detecting the battery cell set, the detection including performing polarity detection on the battery cell set, completing the arrangement if the detection result is pass, and adjusting the battery cell set if the detection result is fail, placing the battery cell set on a welding table, providing a plurality of initial PV ribbons arranged at intervals along a first direction, the initial PV ribbons extending along a second direction, cutting the plurality of initial PV ribbons to form a plurality of PV ribbons, and cutting the plurality of initial PV ribbons from one side of the plurality of initial PV ribbons along the first direction. determining a cutting position of an odd-numbered initial PV ribbon, counted from a same side of the initial PV ribbons along the first direction, as a first position, and a cutting position of an even-numbered initial PV ribbon, counted from a same side of the initial PV ribbons along the first direction, as a second position; controlling each of the PV ribbons to move along the second direction, so that two adjacent PV ribbons in the second direction have a pitch to form a PV ribbon set; transporting the PV ribbon set to the battery cell set such that each of the PV ribbons contacts an adjacent battery cell and at least one of the PV ribbons contacts the battery cell located at an edge; and welding each of the PV ribbons of the multiple PV ribbons to a corresponding battery cell in the battery cell set to form a cell string.

[0006] In some embodiments, the first location is different from the second location, and a distance in the second direction between adjacent break points at the first location and the second location is between 50 mm and 110 mm.

[0007] In some embodiments, after each of the PV ribbons is controlled to move along the second direction, the pitch of two adjacent PV ribbons in the second direction is between 8 mm and 15 mm.

[0008] In some embodiments, detecting the battery cell set further includes performing visual detection on the battery cell set, and if the result of the polarity detection and the result of the visual detection are both pass, the detection result is pass; performing visual detection on the battery cell set includes performing visual detection on each of the battery cells in the battery cell set, and if the result of the visual detection of each of the battery cells is pass, the result of the visual detection of the battery cell set is pass, and if the result of the visual detection of any of the battery cells is fail, the result of the visual detection of the battery cell set is fail, removing the battery cell for which the result of the visual detection is fail, adding a new battery cell in the place of the removed battery cell, and verifying that the polarity of the added battery cell is the same as the polarity of the removed battery cell, and performing the visual detection on the battery cell set again until the detection result of the visual detection is pass.

[0009] In some embodiments, performing the polarity detection on the battery cell set includes performing the polarity detection on each battery cell of the battery cell set, and if the polarities of any two adjacent battery cells are different, a result of the polarity detection is pass, and if the polarities of the two adjacent battery cells are the same, a result of the polarity detection is fail, and removing one of the two adjacent battery cells with the same polarity.

[0010] In some embodiments, the method further includes placing a press-on fixture on the PV ribbon set prior to transferring the PV ribbon set to the battery cell set, and further includes transferring the press-on fixture to the battery cell set together with the PV ribbon set when transferring the PV ribbon set to the battery cell set.

[0011] In some embodiments, the provided plurality of battery cells are back-contact cells.

[0012] According to some embodiments of the present disclosure, another aspect of the embodiments of the present disclosure provides a string welding machine, the string welding machine including a conveyor belt, a detection device, a welding mechanism, a PV ribbon drawing mechanism, a cutting mechanism, a PV ribbon separating mechanism, and a transport device, the conveyor belt is used to arrange a plurality of battery cells to form a battery cell set, the battery cell set is located on the conveyor belt, the detection device is used to detect the battery cell set, the detection device includes a polarity detection device, and the polarity detection device is used to perform polarity detection on the battery cell set, the welding mechanism includes a welding table and is used to weld the battery cell set and a PV ribbon set that are to be welded, the PV ribbon drawing mechanism is used to provide a plurality of initial PV ribbons arranged at intervals along a first direction, and the initial PV ribbon is separated from the battery cell set by a second direction. a first cutting device configured to cut odd-numbered initial PV ribbons counted from one side of the initial PV ribbons along the first direction, and a second cutting device configured to cut even-numbered initial PV ribbons counted from the same side of the initial PV ribbons along the first direction, wherein the first cutting device cuts at a first position and the second cutting device cuts at a second position; the PV ribbon separating mechanism is configured to control each of the PV ribbons to move along the second direction Y to form a PV ribbon set; and the conveying mechanism is configured to convey the PV ribbon set to the battery cell set such that each of the PV ribbons contacts an adjacent battery cell and at least one of the PV ribbons contacts an edge-located battery cell.

[0013] In some embodiments, the conveying device includes a plurality of micro clamps, the plurality of micro clamps arranged along the same straight line in the second direction being one micro clamp set, and when the conveying device moves the PV ribbon set to the battery cell set, the plurality of micro clamps convey the plurality of PV ribbons by clamping them.

[0014] In some embodiments, when the transport device transports the PV ribbon set to the battery cell set, at least two adjacent micro clamps in one micro clamp set clamp the same PV ribbon to stretch the PV ribbon. Effect of the Invention

[0015] The technical solution according to the embodiments of the present disclosure has at least the following advantages:

[0016] A cell string welding method according to an embodiment of the present disclosure includes providing a plurality of battery cells, arranging the plurality of battery cells to form a battery cell set, detecting the battery cell set, the detection including polarity detection, completing the arrangement if the detection result is acceptable, and adjusting the battery cell set if the detection result is unacceptable, placing the battery cell set on a welding table, providing a plurality of initial PV ribbons arranged at intervals along a first direction, the initial PV ribbons extending along a second direction, cutting the plurality of initial PV ribbons to form a plurality of PV ribbons, and cutting an odd-numbered initial PV ribbon counted from one side of the plurality of initial PV ribbons along the first direction. The cutting position of the V ribbon is set to a first position, and the cutting position of the even-numbered initial PV ribbons counted along the first direction is set to a second position, each PV ribbon is controlled to move along the second direction to give a pitch to two adjacent PV ribbons in the second direction to form a PV ribbon set, each PV ribbon contacts an adjacent battery cell and at least one PV ribbon contacts a battery cell located at an edge, and each PV ribbon among the plurality of PV ribbons is welded to a corresponding battery cell in the battery cell set to form a cell string. In the prior art, in the process of arranging the PV ribbons, a PV ribbon pulling device needs to be used to perform position shift conversion pulling on the plurality of PV ribbons, specifically, first, arranging the plurality of PV ribbons with intervals at corresponding positions, and then laying these PV ribbons on the battery cells, and then pulling the remaining plurality of PV ribbons to align them at corresponding positions, and then laying these PV ribbons on the battery cells, and finally welding the PV ribbon set to be arranged in a shifted manner with the battery cell set to form a cell string. In the process of pulling and shifting the PV ribbons using the PV ribbon pulling device, the PV ribbons themselves are narrow and have low hardness, so they are very easily bent, resulting in welding misalignment of the PV ribbons in the final welded cell string.In contrast, in the embodiment of the present disclosure, all the initial PV ribbons can be cut and aligned at the same time, without the need to first process each initial PV ribbon to form a PV ribbon set as a whole, and production efficiency can be improved. In addition, when cutting a plurality of initial PV ribbons, the cutting positions of the odd-numbered initial PV ribbons are different from the cutting positions of the even-numbered initial PV ribbons, i.e., the cutting positions of adjacent initial PV ribbons are different, and the cutting positions can be adapted to the positions required for the alignment of the PV ribbons in the subsequent alignment steps. By cutting at the appropriate positions, the distance that the PV ribbons travel in the subsequent steps can be shortened, the stroke of PV ribbon division can be reduced, the risk of the PV ribbons being bent, and the possibility of welding misalignment can be reduced. In addition, in the embodiment of the present disclosure, the battery cells are detected when aligning the battery cells, thereby reducing the risk of problems occurring in the battery cells and increasing the product yield. [Brief description of the drawings]

[0017] One or more embodiments are illustratively described in the figures in the corresponding accompanying drawings, but these illustrative descriptions are not intended to limit the embodiments, and unless otherwise specified, the figures in the accompanying drawings are not limited to scale. In order to more clearly describe the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below, but obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can obtain other drawings based on these drawings without creative labor. [Figure 1] FIG. 1 is a flow chart corresponding to a method for welding a cell string according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram showing a structure corresponding to one step of a cell string welding method according to an embodiment of the present application. [Diagram 3] FIG. 3 is a diagram showing a structure corresponding to one step of a cell string welding method according to an embodiment of the present application. [Figure 4]FIG. 4 is a diagram showing a structure corresponding to one step of a cell string welding method according to an embodiment of the present application. [Diagram 5] FIG. 5 is a diagram showing a structure corresponding to one step of a cell string welding method according to an embodiment of the present application. [Figure 6] FIG. 6 is a diagram showing a structure corresponding to one step of a cell string welding method according to an embodiment of the present application. [Figure 7] FIG. 7 is a diagram showing a structure corresponding to one step of a cell string welding method according to an embodiment of the present application. [Figure 8] FIG. 8 is a diagram showing a structure corresponding to one step of a cell string welding method according to an embodiment of the present application. [Figure 9] FIG. 9 is a diagram showing a structure of a conveyor belt of a string welding machine according to one embodiment of the present application. [Figure 10] FIG. 10 is a diagram showing the structures of a PV ribbon drawing mechanism, a cutting mechanism, and a transport mechanism of a string welding machine according to an embodiment of the present application. [Figure 11] FIG. 11 is a diagram showing a structure of a transport mechanism of a string welding machine according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] As can be seen from the Background of the Invention, conventional cell string welding methods have the problem of making PV ribbons more prone to bending, leading to weld misalignment.

[0019] In the cell string welding method provided in the embodiment of the present application, first, a plurality of battery cells are arranged as a battery cell set, the battery cell set is detected, if the detection is successful, the arrangement is completed, and then the battery cell set is placed on a welding table, then a plurality of initial PV ribbons are provided, the plurality of initial PV ribbons are cut, the odd-numbered initial PV ribbons are cut at a first position, and the even-numbered initial PV ribbons are cut at a second position, and the movement of each PV ribbon is controlled after cutting to form a PV ribbon set, and finally, the PV ribbon set is transported to the battery cell set, and the PV ribbon set is welded to the battery cell set to form a cell string. In this way, the cutting and arrangement processes can be performed simultaneously on the PV ribbons arranged in a staggered manner, which can improve production efficiency, and the different PV ribbons are cut at different positions to reduce the stroke of PV ribbon division, reduce the risk of PV ribbon bending, and finally reduce the possibility of welding misalignment, and the battery cell set is detected to reduce the risk of battery cell problems, which can increase product yield.

[0020] In order to clarify the purpose, technical solutions and advantages of the embodiments of the present invention, the embodiments of the present application will be described in detail below in conjunction with the drawings. However, as those skilled in the art can understand, in order to allow the reader to better understand the present disclosure, many technical details are proposed in the embodiments of the present disclosure, but the technical solution claimed for protection by the present application can be realized without these technical details and various changes and modifications based on the following embodiments.

[0021] 1 and 2, in S1, a plurality of battery cells 100 are provided, and the plurality of battery cells 100 are arranged to form a battery cell set 101.

[0022] In some embodiments, the battery cells 100 provided may be back contact cells. The battery cells 100 provided may be interdigitated back contact (IBC) cells. In an IBC cell, the P / N junction, the substrate, and the contact electrodes of the emitter region are formed in a comb shape on the back surface of the battery. By printing a comb-shaped diffusion mask layer containing boron on the back surface of the battery, the boron on the mask layer is diffused into the N-type substrate to form a p+ region, and phosphorus is diffused into the region where the mask layer is not printed to form an n+ region. The grid lines of the IBC cell are all provided on the back surface of the battery cell, and there is no shielding of the grid lines on the front surface of the battery, which eliminates the light shielding current loss of the metal electrode and maximizes the use of incident photons. Compared with a normal solar cell, the short circuit current of the IBC cell can be increased by about 7%. Because IBC cell is a back contact structure, there is no need to consider the problem of grid line shielding, so the ratio of grid lines can be increased appropriately, the series resistance can be reduced, and the surface passivation and surface light trapping structure can be optimized and designed, so that low front recombination rate and surface reflection can be obtained. In addition, the appearance of IBC battery cell is beautiful, which is especially suitable for integration into photovoltaic architecture.

[0023] From the above, it can be seen that when manufacturing a cell string with back-contact cells, the PV ribbons for connecting the battery cells 100 are all welded to the back surface of the battery cells 100. In addition, when arranging a plurality of battery cells 100 to form a battery cell set 101, the battery cells 100 of the same polarity need to be arranged with a gap between them so that the polarity of any adjacent battery cells 100 in the battery cell set 101 is reversed.

[0024] 2 shows only three battery cells 100 in the battery cell set 101, but does not limit the actual number of battery cells 100 in the battery cell set 101. In an actual production process, the number of battery cells 100 in the battery cell set 101 may be multiple.

[0025] Continuing to refer to FIG. 1 and FIG. 2, in S2, the battery cell set 101 is detected. The detection includes performing polarity detection on the battery cell set 101. If the detection result is acceptable, the arrangement is completed. If the detection result is unacceptable, the battery cell set 101 is adjusted.

[0026] In some embodiments, performing polarity detection on the battery cell set 101 may include performing polarity detection on each battery cell 100 in the battery cell set 101, and if the polarities of any two adjacent battery cells 100 are different, the result of the polarity detection is pass, and if the polarities of the two adjacent battery cells 100 are the same, the result of the polarity detection is fail, and removing one battery cell 100 of the two adjacent battery cells 100 with the same polarity. The polarities of any two adjacent battery cells 100 in the battery cell set 101 that have been polarity detected are both opposite. This makes it possible to avoid a decrease in the yield of the cell string due to the presence of adjacent battery cells 100 with the same polarity in the battery cell set 101. If a phenomenon occurs in which the detection result is fail in the polarity detection process, it indicates that the polarities of the adjacent battery cells 100 are the same. In this case, it is necessary to adjust the arrangement of the battery cell set 101, and the adjustment method is to remove one of the two adjacent battery cells 100 with the same polarity.

[0027] Specifically, the polarity detection step includes a step 1 of detecting a first battery cell 100 in the battery cell set 101 to be arranged and acquiring the polarity of the first battery cell 100, a step 2 of detecting a second battery cell 100 to be arranged and acquiring the polarity of the second battery cell 100, comparing the polarity of the first battery cell 100 with the polarity of the second battery cell 100, and if the polarity of the first battery cell 100 is the same as the polarity of the second battery cell 100, removing the second battery cell 100 and replacing the third battery cell 100 with the second battery cell 100. and further includes step 2 of repeating the detection of this step and entering the next detection step if the polarity of the first battery cell 100 is different from the polarity of the second battery cell 100, and step 3 of detecting the polarity of the third battery cell 100, obtaining the polarity of the third battery cell 100, and comparing the polarity of the third battery cell 100 with the polarity of the second battery cell 100, the comparison step being the same as step 2, and completing the polarity detection when all the battery cells 100 in the battery cell set 101 have been detected and compared. After the polarity detection is completed, the polarities of any two adjacent battery cells 100 in the battery cell set 101 are opposite to each other.

[0028] In some embodiments, detecting the battery cell set 101 may further include performing visual inspection on the battery cell set, and if the polarity detection result and the visual inspection result are both acceptable, the detection result is acceptable. The visual inspection can detect whether the battery cell 100 is defective, and whether there are scratches, chips, and other conditions. By performing visual inspection, it is possible to ensure that each battery cell 100 in the battery cell set 101 has high quality, prevent the battery cell set 101 from having unacceptable battery cells 100, and effectively increase the yield of the finally formed cell string. In addition, detecting the battery cell set 101 may further include other types of inspection, and if each of the inspection results is acceptable, the detection of the battery cell set 101 is acceptable, and if the detection result of any of the detection items is unacceptable, the battery cell set 101 needs to be adjusted accordingly.

[0029] Specifically, performing the appearance detection on the battery cell set 101 may include performing the appearance detection on each battery cell 100 in the battery cell set 101, and if the result of the appearance detection of each battery cell 100 is acceptable, the result of the appearance detection of the battery cell set 101 is acceptable, and if the result of the appearance detection of any battery cell 100 is unacceptable, the result of the appearance detection of the battery cell set 101 is unacceptable, removing the battery cell 100 whose result of the appearance detection is unacceptable, adding a new battery cell 100 in the place of the removed battery cell 100, and performing the appearance detection on the battery cell set 101 again until the polarity of the added battery cell 100 is the same as that of the removed battery cell 100, and the detection result of the appearance detection is acceptable. This realizes performing the appearance detection on each battery cell 100 in the battery cell set 101, and each battery cell 100 in the battery cell set 101 becomes a battery cell 100 that meets the quality standard, thereby effectively increasing the yield of the cell string. After removing the battery cell 100 whose appearance detection result has failed, a battery cell 100 of the same polarity as the removed battery cell 100 needs to be added in place of the removed battery cell 100, because the polarities of any two battery cells 100 in the battery cell set 101 will still be reversed.

[0030] 1 and 3, in S3, the battery cell set 101 is placed on the welding table 210. The welding table 210 is a device for welding the battery cell set 101 and the PV ribbons, and the battery cell set 101 that has been aligned and detected can be placed on the welding table 210 and wait for welding.

[0031] PV ribbons for welding cell strings can be manufactured after the arrangement and placement of the battery cell sets 101 is completed, or simultaneously with the arrangement and placement of the battery cell sets 101. By manufacturing the PV ribbons simultaneously with the arrangement and placement of the battery cell sets 101, production time can be shortened and production efficiency can be improved.

[0032] 1 and 4, in S4, a plurality of initial PV ribbons 111 are provided that are spaced apart from each other along a first direction X, and the initial PV ribbons 111 extend along a second direction Y. After being processed, one initial PV ribbon 111 can be a plurality of PV ribbons 110 that are on the same straight line along the second direction Y in the cell string. In the first direction X, the width of the initial PV ribbon 111 is the same as the width of the PV ribbons 110 in the cell string. In addition, in the first direction X, the pitch between adjacent initial PV ribbons 111 is the pitch between adjacent PV ribbons 110 in the cell string. In the process of making the initial PV ribbons 111 into the PV ribbons 110, it is not necessary to move the PV ribbons 110 along the first direction X, and bending of the PV ribbons 110 due to the movement of the PV ribbons 110 can be reduced.

[0033] 1 and 5, in S5, a plurality of initial PV ribbons 111 are cut to form a plurality of PV ribbons 110, and the cutting positions of odd-numbered initial PV ribbons 111 counted from one side of the plurality of initial PV ribbons 111 along the first direction X are designated as first positions 112, and the cutting positions of even-numbered initial PV ribbons 111 counted from the same side of the plurality of initial PV ribbons 111 along the first direction X are designated as second positions 113.

[0034] In the cell string, a plurality of PV ribbons 110 for connecting the battery cells 100 to form the cell string are arranged crosswise, that is, the arrangement positions of the plurality of PV ribbons 110 located on adjacent straight lines in the first direction X are different, and the arrangement positions of the plurality of PV ribbons 110 located on straight lines spaced apart from each other in the first direction X are the same. From one side of the plurality of initial PV ribbons 111, the arrangement positions of the odd-numbered initial PV ribbons 111 counted along the first direction X are the same, and the arrangement positions of the even-numbered initial PV ribbons 111 counted along the first direction X are the same. Therefore, when the plurality of initial PV ribbons 111 are cut to obtain the plurality of PV ribbons 110, the odd-numbered initial PV ribbons 111 and the even-numbered initial PV ribbons 111 can be set to different cutting positions, and the cutting positions can be set according to the arrangement positions of the PV ribbons 110 in the cell string. This can effectively reduce the movement stroke of the PV ribbons 110 during the process of arranging the PV ribbons 110 after cutting, reduce the bending of the PV ribbons 110 during the PV ribbon separation process, and ultimately reduce the risk of welding misalignment occurring in the cell strings.

[0035] In some embodiments, first location 112 and second location 113 may be the same. Making first location 112 and second location 113 the same can somewhat simplify the apparatus for cutting initial PV ribbon 111 and reduce production costs.

[0036] 5, in some embodiments, the first location 112 is different from the second location 113, and the distance between adjacent cut points at the first location 112 and the second location 113 in the second direction Y may be between 50 mm and 110 mm. For example, the distance between adjacent cut points at the second location 113 and the first location 112 in the second direction Y may be 50 mm, 70 mm, 90 mm, 100 mm, 110 mm, etc. The distance between adjacent cut points is as shown in the figure. If the distance between adjacent cutting points at the second position 113 and the first position 112 in the second direction Y is too small, at least one set of PV ribbons 110 must travel a long distance between the PV ribbons 110 cut from the odd-numbered initial PV ribbons 11 and the PV ribbons 110 cut from the even-numbered initial PV ribbons 111 before the misaligned arrangement of the PV ribbons 110 can be completed, resulting in a large PV ribbon division distance, a high risk of the PV ribbons 110 being bent during PV ribbon division, and a high risk of welding misalignment occurring in the finally formed cell string. If the distance between adjacent cutting points at the second position 113 and the first position 112 in the second direction Y is too large, the PV ribbons 110 must travel a long distance before the misaligned arrangement of the PV ribbons 110 can be completed, resulting in a large PV ribbon division distance, a high risk of the PV ribbons 110 being bent during PV ribbon division, and a high risk of welding misalignment occurring in the finally formed cell string. Therefore, in the second direction Y, the distance between adjacent cutting points at first position 112 and second position 113 needs to be selected in an appropriate range, and the distance between the adjacent cutting points can be selected according to the arrangement of the PV ribbons 110 in the cell string. When the distance between adjacent cutting points at first position 112 and second position 113 is 50 mm to 110 mm, it can effectively reduce the movement stroke of the PV ribbons 110, reduce the risk of bending of the PV ribbons 110 during the PV ribbon separation process, and reduce the risk of welding misalignment occurring in the finally formed cell string.

[0037] 1 and 6, in S6, each PV ribbon 110 is controlled to move along the second direction Y, and two adjacent PV ribbons 110 in the second direction Y are pitched to form a PV ribbon set 114. The arrangement of the PV ribbon set 114 is, in other words, the arrangement of the multiple PV ribbons 110 in the cell string 102. First, the multiple PV ribbons 110 required for the cell string are arranged, and then the arranged PV ribbon set 114 is moved to the battery cell set 101, thereby reducing the moving distance of each PV ribbon 110 in the process of dividing the PV ribbons in the displaced arrangement, and reducing the risk of the PV ribbons 110 being bent.

[0038] Since the distance in the first direction X between the multiple initial PV ribbons 111 formed in the above steps is the same as the distance between adjacent PV ribbons 110 in the first direction X of the cell string, when moving the PV ribbons 110, it is not necessary to move the PV ribbons 110 along the first direction X, but only by moving them along the second direction Y, which can reduce the risk of bending the PV ribbons 110 during movement. In addition, in the process of cutting the PV ribbons 110, by setting different cutting positions for the PV ribbons 110 that are spaced apart in the first direction X and have different arrangements in the cell string, it is possible to reduce the movement distance of the PV ribbons 110 in the second direction Y, and further reduce the risk of bending the PV ribbons 110 during the movement process, and reduce the risk of welding misalignment in the finally formed cell string.

[0039] Continuing to refer to FIG. 6, in some embodiments, after each PV ribbon 110 is controlled to move along the second direction Y, the pitch of two adjacent PV ribbons 110 in the second direction Y may be 8 mm to 15 mm. The pitch of two adjacent PV ribbons 110 in the second direction Y is shown in FIG. 6. For example, after the movement, the pitch of two adjacent PV ribbons 110 in the second direction Y may be 5 mm, 9 mm, 10 mm, 12 mm, 15 mm, etc. After the movement, the pitch of two adjacent PV ribbons 110 in the second direction Y may be set according to the arrangement of the cell string. If the pitch of two adjacent PV ribbons 110 in the second direction Y is too small, the distance between adjacent battery cells 100 in the cell string formed by welding in a later step will be small, and there will be a risk of short circuit between the adjacent battery cells 100, which will reduce the stability of the cell string to a certain extent. If the pitch in the second direction Y of two adjacent PV ribbons 110 is too large, the distance between adjacent battery cells 100 in the cell string formed by welding in the subsequent step will be large, the size of the entire cell string will also be large, and the size of the photovoltaic module finally manufactured from the cell string will also be too large, which will affect the use of the product and result in material waste. Therefore, after moving, the pitch in the second direction Y of two adjacent PV ribbons 110 needs to be selected in an appropriate range, and if the pitch in the second direction Y of two adjacent PV ribbons 110 is 8 mm to 15 mm, the cell string will not have a large short circuit risk, and the size of the cell string will not be too large to affect the use of the product.

[0040] In some embodiments, the method may further include arranging a press-type fixture (not shown) on the PV ribbon set 114 before transferring the PV ribbon set 114 to the battery cell set 101. The press-type fixture is one of the tool devices, and is used to press the PV ribbon set 114 arranged in the above step. By arranging the press-type fixture on the PV ribbon set 114, all the PV ribbons 110 in the PV ribbon set 114 can be pressed to the same plane, and when the PV ribbon set 114 is moved to the battery cell set 101, the PV ribbons 110 in the PV ribbon set 114 can better contact the surfaces of the battery cells 100 in the battery cell set 101, which helps the subsequent welding process to proceed smoothly.

[0041] When transporting the PV ribbon set 114 to the battery cell set 101, a press-type fixture may be further transported to the battery cell set 101 together with the PV ribbon set 114. The press-type fixture presses all of the PV ribbons 110 in the PV ribbon set 114, and by transporting the press-type fixture together with the PV ribbon set 114 to the battery cell set 101, the PV ribbons 110 in the PV ribbon set 114 can better contact the surfaces of the battery cells 100 in the battery cell set 101, and displacement of the arrangement of the PV ribbons 110 in the PV ribbon set 114 can be avoided in the process of transporting the PV ribbon set 114.

[0042] 1 and 7, in S7, the PV ribbon set 114 is transported to the battery cell set 101 so that each PV ribbon 110 contacts an adjacent battery cell 100 and at least one PV ribbon 110 contacts a battery cell 100 located at an edge. In the process of transporting the PV ribbon set 114 to the battery cell set 101, the relative positional relationship of each PV ribbon 110 in the PV ribbon set 114 does not change, and the PV ribbons 110 in the PV ribbon set 114 form a relative positional relationship in which they are arranged with their positions shifted only by the above-mentioned PV ribbon division step. The PV ribbons 110 are not bent by moving the PV ribbons 110 in a horizontal plane without changing the relative positional relationship of the PV ribbon set 114 during the transport process. In this way, by first setting the relative positions of the PV ribbon sets 114 and then transporting the entire arranged PV ribbon set 114 to the battery cell set 101, the moving distance of the PV ribbons 110 when they are arranged out of position in the horizontal plane can be effectively reduced, and the risk of the PV ribbons 110 being bent can be reduced.

[0043] Before transferring the PV ribbon set 114, the battery cell set 101 may be placed on the welding table 210. Therefore, transferring the PV ribbon set 210 to the battery cell set 101, i.e., transferring the PV ribbon set 114 to the welding table 210, is useful for welding the battery cell set 101 and the PV ribbon set 114 to form a cell string in a subsequent step. After the PV ribbon set 114 is transported to the battery cell set 101, the PV ribbons 110 that are not located at the edges in the second direction Y can connect two adjacent battery cells 100, and on one side of the PV ribbon set 114, the odd-numbered PV ribbons 110 and the even-numbered PV ribbons 110 counted along the first direction X connect two different adjacent battery cells 100, and in the second direction Y, the PV ribbons 110 located at the edges may only connect the battery cells 100 located at the edges, and the PV ribbons 110 connected only to the battery cells 100 located at the edges may have one end connected to the battery cells 100 and the other end extending outside the battery cells 100 to be electrically connected to another mechanism.

[0044] In some embodiments, PV ribbons 110 of PV ribbon set 114 can be stretched during the process of transporting PV ribbon set 114. This can reduce possible deformation of PV ribbons 110 during the previous misalignment movement process, further reducing the risk of bending PV ribbons 110 and reducing the possibility of welding misalignment of PV ribbons 110 to the cell strings.

[0045] 1 and 8, in S8, each PV ribbon 110 of the multiple PV ribbons 110 is welded to a corresponding battery cell 100 in the battery cell set 101 to form a cell string 102. The PV ribbons 110 can electrically connect the arranged battery cell sets 101 so that the battery cell sets 101 can form a complete cell string 102. Compared with a single battery cell 100, the cell string 102 can achieve better power supply capability and has higher performance. Since the PV ribbon set 114 and the battery cell set 101 are both located on the welding table 210, the welding table 210 can be directly used to perform welding processes on the battery cell set 101 and the PV ribbon set 114.

[0046] Note that, although the drawing shows only a cell string 102 having three battery cells 100, this does not represent the number of battery cells 100 actually present in the cell string 102. The actual cell string 102 may have multiple battery cells 100.

[0047] 8, after forming cell strings 102 by welding, a plurality of cell strings 102 may be connected to form a battery cell set 103. A bus bar may be used as a structure for connecting the plurality of cell strings 102. Note that, although the drawing shows only a battery cell set 103 in which two cell strings 102 are connected, this does not represent the number of cell strings 102 actually present in the battery cell set 103, and the actual battery cell set 103 may have a plurality of cell strings 102.

[0048] In some embodiments, connecting multiple cell strings 102 as a battery cell set 103 may include an AB string connection method, where A refers to the positive electrode of the cell string 102 and B refers to the negative electrode of the cell string 102, and the AB string refers to connecting the positive electrode and the negative electrode. The AB string connection method can increase the output voltage and power of the battery cell set 103 and reduce current loss.

[0049] In the cell string welding method provided in the embodiment of the present application, first, a plurality of battery cells are provided, the plurality of battery cells are arranged as a battery cell set, the battery cell set is detected, if the detection is successful, the arrangement is completed, and then the battery cell set is placed on a welding table, then a plurality of initial PV ribbons are provided, the plurality of initial PV ribbons are cut to form a plurality of PV ribbons, the odd-numbered initial PV ribbons are cut at a first position, the even-numbered initial PV ribbons are cut at a second position, the movement of each PV ribbon is controlled to form a PV ribbon set, and finally, the PV ribbon set is transported to the battery cell set for welding to form a cell string. In this way, all the PV ribbons are processed at the same time to improve production efficiency, different PV ribbons are cut at different positions to reduce the stroke of PV ribbon division, reduce the risk of PV ribbon bending, and finally reduce the possibility of welding deviation, and the battery cell set is detected to increase the product yield.

[0050] Accordingly, another embodiment of the present application further provides a string welder that can be used to realize the welding method for the cell string in the above embodiment. Hereinafter, the string welder in another embodiment of the present application will be described in detail with reference to the drawings. However, for the same or similar parts as those in the above embodiment, the corresponding descriptions in the above embodiment may be referred to, and therefore will not be described repeatedly here.

[0051] FIG. 9 is a diagram showing the structure of a cell string set in a string welding machine according to one embodiment of the present application when it is arranged on a conveyor belt, and FIG. 10 is a diagram showing the structures of a PV ribbon pull-out mechanism, cutting mechanism, and transport mechanism of a string welding machine according to one embodiment of the present application, and FIG. 11 does not show the complete cutting mechanism, and the cutting structure also includes multiple micro clamps that are not shown.

[0052] As shown in FIGS. 9 and 10 , the string welding machine includes a conveyor belt 220, a detection device (not shown), a welding mechanism, a PV ribbon drawing mechanism 230, a cutting mechanism 240, a PV ribbon separating mechanism, and a transport device, in which the conveyor belt 220 is used to arrange a plurality of battery cells 100 to form a battery cell set 101, the battery cell set 101 is located on the conveyor belt 220, the detection device is used to detect the battery cell set 101, the detection device includes a polarity detection device, which is used to perform polarity detection on the battery cell set 103, the welding mechanism includes a welding table 210 (see FIG. 3 ) and is used to weld the battery cell set 101 and the PV ribbon set 114 that are to be welded, the PV ribbon drawing mechanism 230 is used to provide a plurality of initial PV ribbons 111 arranged at intervals along a first direction X, the initial PV ribbon 111 extends along a second direction Y, and the PV ribbon separating mechanism 230 is used to separate the plurality of initial PV ribbons 111 from one another. The mechanism 240 is used to cut the plurality of initial PV ribbons 111 to form the plurality of PV ribbons 110, and the cutting mechanism 240 includes a first cutting device 241 that cuts odd-numbered initial PV ribbons 111 counted from one side of the plurality of initial PV ribbons 111 along the first direction X, and a second cutting device 242 that cuts even-numbered initial PV ribbons 111 counted from the same side of the plurality of initial PV ribbons 111 along the first direction X, where the first cutting device 241 is at a first position a first cutting device 242 cuts at a second position, a PV ribbon separating mechanism (not shown) is used to control each PV ribbon 110 to move along a second direction Y to form a PV ribbon set 114, and a conveying mechanism is used to convey the PV ribbon set 114 to the battery cell set 101 such that each PV ribbon 110 contacts an adjacent battery cell 100 and at least one PV ribbon 110 contacts an edge-located battery cell 100.

[0053] 9, the battery cell sets 101 may be arranged on the conveyor belt 220 to form the battery cell set 101. In addition, a detection device may be disposed on the conveyor belt 220, and the battery cell sets 101 may be detected using the detection device while being arranged, and the detection device may include a polarity detection device and an appearance detection device, and when the polarity detection and appearance detection of the polarity detection device and the appearance detection device are both successful, the detection result is successful and the arrangement of the battery cell set 101 may be completed.

[0054] In some embodiments, the conveyor belt 220 can be connected to a welding mechanism, and the battery cell sets 103 arranged on the conveyor belt 220 can be transported via the conveyor belt 220 to a welding table 210 in the welding mechanism and used to be welded in a subsequent process.

[0055] 10 , the PV ribbon-drawing mechanism 230 can simultaneously form a plurality of initial PV ribbons 111 that are arranged at intervals along the first direction X and extend along the second direction Y. In the process of forming the plurality of initial PV ribbons 111 by the PV ribbon-drawing mechanism 230, the PV ribbon-drawing mechanism 230 can move along the second direction Y, and form a plurality of initial PV ribbons 111 extending along the second direction Y during the movement process.

[0056] The cutting mechanism 240 can be composed of multiple cutters at different positions. As can be seen, the multiple PV ribbons 110 in the cell string 102 are arranged in a staggered manner, that is, the PV ribbons 110 at odd positions along the first direction X are arranged differently from the PV ribbons 110 at even positions along the first direction X. Thus, a first cutting device 241 for cutting the odd-numbered initial PV ribbons 111 and a second cutting device 242 for cutting the even-numbered initial PV ribbons 111 can be provided, with the cutting position of the first cutting device 241 being the first position 112 and the cutting position of the second cutting device 242 being the second position 112. The first position 112 and the second position 113 can be set according to the arrangement of the PV ribbons in the cell string 102. By rationally setting the first position 112 and the second position 113, the movement distance of the PV ribbons 110 when the PV ribbons 110 are moved and arranged after cutting can be reduced, the risk of the PV ribbons 110 being bent, and the risk of welding misalignment of the PV ribbons 110 in the final formed cell string 102 can be reduced.

[0057] The PV ribbon dividing mechanism can move the cut PV ribbon 110 along the second direction Y. When the PV ribbon unwinding mechanism 230 forms a plurality of initial PV ribbons 111, the distance of the plurality of initial PV ribbons 111 in the first direction X is the distance of the PV ribbons 110 in the cell string 102 in the first direction X. Therefore, the PV ribbons 110 do not need to move along the first direction X after cutting, and the risk of bending the PV ribbons 110 can be reduced. In addition, when cutting the initial PV ribbons 111, different cutting positions can be set for the odd-numbered initial PV ribbons 111 and the even-numbered initial PV ribbons 111 according to the arrangement positions of the PV ribbons 110 in the cell string 102. This can reduce the movement stroke of the PV ribbons 110 during PV ribbon division, further reducing the risk of bending the PV ribbons 110, and reducing the possibility of welding misalignment of the PV ribbons 110 in the cell string 102.

[0058] FIG. 11 is a diagram showing a structure in which micro clamps clamp and transport a PV ribbon in a string welding machine according to an embodiment of the present application.

[0059] 10 and 11 , in some embodiments, the conveying device may further include a plurality of micro clamps 251, where the plurality of micro clamps 251 arranged along the same straight line in the second direction Y constitute one micro clamp set 250, and when the conveying device moves the PV ribbon set 114 to the battery cell set 101, the plurality of micro clamps 251 convey the plurality of PV ribbons 110 while sandwiching them. When the conveying device conveys the PV ribbon set 114 to the battery cell 100, the relative positional relationship of the plurality of PV ribbons 110 in the PV ribbon set 114 may not be changed. When the plurality of micro clamps 251 convey the plurality of PV ribbons 110 while sandwiching them, the movement trajectory of each of the plurality of micro clamps 251 may be the same.

[0060] 11 , in some embodiments, when the conveying device conveys the PV ribbon set 114 to the battery cell set 101, at least two adjacent micro clamps 251 in one micro clamp set 250 can clamp the same PV ribbon 110 to stretch the PV ribbon 110. When the two micro clamps 251 clamp the same PV ribbon 110, the two micro clamps 251 are positioned on the same straight line in the second direction Y and can stretch the PV ribbon 110 along the second direction Y. This can reduce deformation that may occur in the PV ribbon 110 during the previous PV ribbon separating movement, further reduce the risk of the PV ribbon 110 being bent, and further reduce the possibility of welding misalignment of the PV ribbon 110 occurring in the cell string.

[0061] In an embodiment of the present application, a string welding machine is provided, the string welding machine including a conveyor belt for arranging the cell string set, a detection device for detecting the battery cell set, a welding mechanism for welding the PV ribbon and the battery cell, a PV ribbon drawing mechanism for forming an initial PV ribbon, a cutting mechanism for cutting the initial PV ribbon to form a PV ribbon, the cutting mechanism including a first cutting device for cutting at a first position and a second cutting device for cutting at a second position, a PV ribbon dividing mechanism for controlling the movement of the PV ribbon, and a conveying mechanism for conveying the PV ribbon set to the battery cell set, whereby all the PV ribbons can be processed at the same time to improve production efficiency, a cutting device for cutting at different positions for different PV ribbons can be used, the stroke of PV ribbon dividing can be reduced, the risk of bending the PV ribbon can be reduced, and the possibility of final welding deviation can be reduced, and the detection device can be used to detect the battery cell set to improve product yield.

[0062] Those skilled in the art will understand that the above embodiments are specific examples for realizing the present disclosure, but in actual application, various changes in form and details are possible without departing from the spirit and scope of the present invention. Since any person skilled in the art can make changes and modifications without departing from the spirit and scope of the present invention, the protection scope of the present invention should be based on the scope limited by the claims.

Claims

1. providing a plurality of battery cells and arranging the plurality of battery cells to form a battery cell set; Detecting the battery cell set, the detection including performing polarity detection on the battery cell set, completing the arrangement if the detection result is pass, and adjusting the battery cell set if the detection result is fail; placing the battery cell set on a welding table; providing a plurality of initial PV ribbons arranged at intervals along a first direction, the initial PV ribbons extending along a second direction; cutting the initial PV ribbons to form a plurality of PV ribbons, and setting a cutting position of an odd-numbered initial PV ribbon counted from one side of the initial PV ribbons along the first direction as a first position, and setting a cutting position of an even-numbered initial PV ribbon counted from the same side of the initial PV ribbons along the first direction as a second position; controlling each of the PV ribbons to move along the second direction, so that two adjacent PV ribbons in the second direction have a pitch to form a PV ribbon set; conveying the PV ribbon set to the battery cell set such that each PV ribbon contacts an adjacent battery cell and such that at least one PV ribbon contacts an edge-located battery cell; and welding each of the PV ribbons of the plurality of PV ribbons to a corresponding battery cell in the battery cell set to form a cell string. A method for welding a cell string comprising the steps of:

2. the first location is different from the second location, and a distance between adjacent break points at the first location and the second location in the second direction is between 50 mm and 110 mm; The method for welding a cell string according to claim 1 .

3. After controlling each of the PV ribbons to move along the second direction, the pitch of two adjacent PV ribbons in the second direction is 8 mm to 15 mm. The method for welding a cell string according to claim 1 .

4. The detecting the battery cell set further includes performing an appearance detection on the battery cell set, and if a result of the polarity detection and a result of the appearance detection are both pass, the detection result is pass; performing appearance detection on the battery cell set, performing the appearance detection for each of the battery cells in the battery cell set, and if the result of the appearance detection for each of the battery cells is pass, the result of the appearance detection for the battery cell set is pass, and if the result of the appearance detection for any of the battery cells is fail, the result of the appearance detection for the battery cell set is fail, removing the battery cell for which the result of the appearance detection is fail, adding a new battery cell in place of the removed battery cell, and making sure that the polarity of the added battery cell is the same as the polarity of the removed battery cell; and performing the appearance inspection again on the battery cell set until a detection result of the appearance inspection is passed. The method for welding a cell string according to claim 1 .

5. performing the polarity detection on the battery cell set includes performing the polarity detection on each of the battery cells of the battery cell set, and if the polarities of any two adjacent battery cells are different, the result of the polarity detection is pass, and if the polarities of the two adjacent battery cells are the same, the result of the polarity detection is fail, and removing one of the two adjacent battery cells having the same polarity. The method for welding a cell string according to claim 1 .

6. placing a press-fit fastener on the PV ribbon set prior to transferring the PV ribbon set to the battery cell set; and transporting the press-fit fixture together with the PV ribbon set to the battery cell set when transporting the PV ribbon set to the battery cell set. The method for welding a cell string according to claim 1 .

7. The battery cells provided are back-contact cells. The method for welding a cell string according to claim 1 .

8. a conveyor belt, a detection device, a welding mechanism, a PV ribbon drawing mechanism, a cutting mechanism, a PV ribbon separating mechanism, and a transport device; the conveyor belt is used for arranging a plurality of battery cells to form a battery cell set, the battery cell set being positioned on the conveyor belt; the detection device is used to detect the battery cell set, the detection device includes a polarity detection device, and the polarity detection device is used to perform polarity detection on the battery cell set; the welding mechanism includes a welding table and is used to weld the battery cell set and the PV ribbon set that are welding objects; the PV ribbon withdrawal mechanism is used to provide a plurality of initial PV ribbons spaced apart along a first direction, the initial PV ribbons extending along a second direction; the cutting mechanism is used to cut a plurality of the initial PV ribbons to form a plurality of PV ribbons, the cutting mechanism including a first cutting device configured to cut odd-numbered initial PV ribbons counted from one side of the plurality of initial PV ribbons along the first direction, and a second cutting device configured to cut even-numbered initial PV ribbons counted from the same side of the plurality of initial PV ribbons along the first direction, wherein the first cutting device cuts at a first position and the second cutting device cuts at a second position; the PV ribbon separating mechanism is used to control the movement of each of the PV ribbons along the second direction Y to form a PV ribbon set; the transport mechanism is used to transport the PV ribbon set to the battery cell set such that each PV ribbon contacts an adjacent battery cell and at least one PV ribbon contacts an edge-located battery cell. String welding machine characterized by:

9. the conveying device includes a plurality of micro clamps, the plurality of micro clamps arranged along the same straight line in the second direction constitute one micro clamp set, and when the conveying device moves the PV ribbon set to the battery cell set, the plurality of micro clamps convey the PV ribbons by clamping them.

9. The string welder of claim 8.

10. when the conveying device conveys the PV ribbon set to the battery cell set, at least two adjacent micro clamps in one micro clamp set clamp the same PV ribbon and stretch the PV ribbon; 10. The string welder of claim 9.

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