CN220873586U - Back contact battery and battery string - Google Patents

Abstract

The utility model discloses a back contact battery and a battery string, which relate to the technical field of solar batteries and are used for solving the problem that the manufacturing cost of a battery or a photovoltaic module is increased due to the fact that the printing and drying procedures are required to be added for printing insulating glue. The back contact battery includes: battery body, main grid and thin bars. The main grid comprises a plurality of first polarity main grids and a plurality of second polarity main grids, and the thin grids comprise a plurality of first polarity thin grids and a plurality of second polarity thin grids. The first polarity fine grid is connected with the first polarity main grid, and the second polarity fine grid is connected with the second polarity main grid. A second polarity additional fine gate extending in the first direction and connected only to the second polarity main gate is included between the free end of the at least one first polarity fine gate and the second polarity main gate. And/or including a first polarity additional fine gate extending in a first direction between the free end of the at least one second polarity fine gate and the first polarity main gate and connected only to the first polarity main gate, the first direction being different from the second direction.

Description

Back contact battery and battery string

Technical Field

The utility model relates to the technical field of solar cells, in particular to a back contact cell and a cell string.

Background

Existing back contact cells include metal wrap through (METAL WRAP through, abbreviated MWT) cells, interdigitated back contact (INTERDIGITATED BACK CONTACT, abbreviated IBC) cells, and the like. The IBC battery is a back contact type photovoltaic battery with positive and negative metal electrodes arranged on the back of the battery in an interdigital mode, and the front of the battery is shielded by no grid line, so that the optical loss is effectively reduced, and the power generation efficiency is improved.

In the prior art, in order to avoid welding a welding strip in the process of manufacturing an IBC battery, the welding strip is connected with two electrodes with different polarities at the same time, and insulating glue is usually printed on two ends of a fine grid.

But the printing of the insulating paste requires a separate printing and drying process, resulting in an increased manufacturing cost of the IBC cell or photovoltaic module.

Disclosure of utility model

The utility model aims to provide a back contact battery and a battery string, which are used for reducing or avoiding printing insulating glue so as to reduce the manufacturing cost of an IBC battery or a photovoltaic module.

To achieve the above object, in a first aspect, the present utility model provides a back contact battery. The back contact battery includes: and a battery body having a plurality of main grids and a plurality of fine grids formed on a backlight surface of the battery body. The main grid comprises a plurality of first polarity main grids and a plurality of second polarity main grids, wherein the first polarity main grids and the second polarity main grids extend along a second direction and are alternately arranged at intervals along the first direction, and the first direction is different from the second direction. The fine grid comprises a plurality of first polarity fine grids and a plurality of second polarity fine grids, wherein the first polarity fine grids and the second polarity fine grids extend along a first direction, are alternately arranged at intervals along a second direction, and are arranged in a crossing manner along the second direction. The first polarity fine grid is connected with the first polarity main grid, and the second polarity fine grid is connected with the second polarity main grid. Wherein the second polarity additional fine gate extending in the first direction and connected only to the second polarity main gate is included between the free end of the at least one first polarity fine gate and the second polarity main gate. And/or including a first polarity additional fine gate extending in the first direction between the free end of the at least one second polarity fine gate and the first polarity main gate and connected only to the first polarity main gate.

As can be seen from the above description, in the back contact battery provided by the present utility model, the length of the first polarity fine grid (and/or the length of the second polarity fine grid) is reduced in the first direction compared to the length of the first polarity fine grid (and/or the length of the second polarity fine grid) in the prior art. At this time, the distance between the first polarity main gate and the free end of the second polarity fine gate (and/or the distance between the second polarity main gate and the free end of the first polarity fine gate) is increased. Based on this, when the welding strip is connected with the first polarity main grid correspondingly, compared with the prior art, the distance between the welding strip and the free end of the second polarity fine grid is increased, and then the probability that the welding strip is connected with the first polarity main grid and the second polarity main grid simultaneously can be reduced or eliminated, so that the risk of short circuit of the back contact battery is reduced or eliminated. At this time, compared with the prior art, the method can reduce or avoid printing insulating glue on the two ends of the thin grid and the cross-region electrode so as to reduce the manufacturing cost of the back contact battery or the photovoltaic module. It should be understood that the same applies to the connection of the bonding pad and the second polarity main gate, and the description thereof will not be repeated here. Further, since the back contact battery includes the first polarity additional fine grid and/or the second polarity additional fine grid, the capability of the fine grid to collect carriers can be improved, and further the battery efficiency of the back contact battery can be improved, compared to the case where only the length of the first polarity fine grid and/or the length of the second polarity fine grid is shortened, but the first polarity additional fine grid and/or the second polarity additional fine grid is not increased.

In one implementation, when the length of the first polarity fine grid is greater than the length of the second polarity additional fine grid, the ratio of the length of the second polarity additional fine grid to the maximum width of the second polarity main grid correspondingly connected with the second polarity additional fine grid is greater than or equal to 0.5 and less than or equal to 3; the length direction of the second polarity additional fine grid and the width direction of the second polarity main grid are consistent with the first direction.

Under the condition of adopting the technical scheme, the ratio is larger than or equal to 0.5, so that the distance between the welding strip or the welding pad and the free end of the first polarity fine grid can meet the actual requirement, and when the welding strip or the welding pad is correspondingly connected with the second polarity main grid, the probability that the welding strip or the welding pad is simultaneously connected with the first polarity main grid and the second polarity main grid can be reduced or eliminated, and the risk of short circuit of the back contact battery is further reduced or eliminated. Further, since the ratio is less than or equal to 3, the loss of the effective PN junction area of the second polarity additional thin gate region correspondingly connected with the second polarity main gate can be reduced or avoided. That is, the collection capability of all the fine gates included in the back contact battery to carriers can be improved, and the collection efficiency of current can be improved.

In one implementation, when the length of the second polarity fine grid is greater than the length of the first polarity additional fine grid, the ratio of the length of the first polarity additional fine grid to the maximum width of the first polarity main grid correspondingly connected with the first polarity additional fine grid is greater than or equal to 0.5 and less than or equal to 3; the length direction of the first polarity additional fine grid and the width direction of the first polarity main grid are consistent with the first direction.

Under the condition of adopting the technical scheme, the ratio is larger than or equal to 0.5, so that the distance between the welding strip or the welding pad and the free end of the second polarity fine grid can meet the actual requirement, and when the welding strip or the welding pad is correspondingly connected with the first polarity main grid, the probability that the welding strip or the welding pad is simultaneously connected with the first polarity main grid and the second polarity main grid can be reduced or eliminated, and the risk of short circuit of the back contact battery is further reduced or eliminated. Further, since the ratio is less than or equal to 3, the loss of the effective PN junction area of the first polarity additional thin gate region correspondingly connected with the first polarity main gate can be reduced or avoided. That is, the collection capability of all the fine gates included in the back contact battery to carriers can be improved, and the collection efficiency of current can be improved.

In one implementation, when the length of the first polarity fine grid is greater than the length of the second polarity additional fine grid, the length of the second polarity additional fine grid is greater than or equal to 0.1mm and less than or equal to 5mm. The length direction of the first polarity fine grid and the length direction of the second polarity additional fine grid are consistent with the first direction.

Under the condition of adopting the technical scheme, because the length of the second polarity additional fine grid is greater than or equal to 0.1mm, the distance between the welding strip or the welding pad and the free end of the first polarity fine grid can meet the actual requirement at the moment, so that when the welding strip or the welding pad is correspondingly connected with the second polarity main grid, the probability of simultaneously connecting the welding strip or the welding pad with the first polarity main grid and the second polarity main grid can be reduced or eliminated, and the risk of short circuit of the back contact battery is further reduced or eliminated. Further, since the length of the second polarity additional fine gate is less than or equal to 5mm, the loss of the effective PN junction area of the second polarity additional fine gate region correspondingly connected to the second polarity main gate can be reduced or avoided. That is, the collection capability of all the fine gates included in the back contact battery to carriers can be improved, and the collection efficiency of current can be improved.

In one implementation, when the length of the second polarity fine grid is greater than the length of the first polarity additional fine grid, the length of the first polarity additional fine grid is greater than or equal to 0.1mm and less than or equal to 5mm. The length direction of the second polarity fine grid and the length direction of the first polarity additional fine grid are consistent with the first direction.

Under the condition of adopting the technical scheme, because the length of the additional fine grid with the first polarity is larger than or equal to 0.1mm, the distance between the welding strip or the welding pad and the free end of the fine grid with the second polarity can meet the actual requirement at the moment, so that when the welding strip or the welding pad is correspondingly connected with the main grid with the first polarity, the probability that the welding strip or the welding pad is simultaneously connected with the main grid with the first polarity and the main grid with the second polarity can be reduced or eliminated, and the risk of short circuit of a back contact battery is further reduced or eliminated. Further, since the length of the first polarity additional fine gate is less than or equal to 5mm, a loss of the effective PN junction area of the first polarity additional fine gate region correspondingly connected to the first polarity main gate can be reduced or avoided. That is, the collection capability of all the fine gates included in the back contact battery to carriers can be improved, and the collection efficiency of current can be improved.

In one implementation, a space is provided between the free end of the first polar fine grid and the free end of the second polar additional fine grid adjacent to the first polar fine grid, wherein the space is greater than 0 micrometers and less than or equal to 100 micrometers.

Under the condition of adopting the technical scheme, the distance is larger than 0 micrometers, so that the connection of the first polarity fine grid and the second polarity fine grid can be avoided, and the short circuit of the back contact battery is avoided. Further, since the pitch is less than or equal to 100 μm, it is possible to avoid that the sum of the lengths of the first polarity fine gate and the second polarity additional fine gate is too small due to the excessively large pitch size when the distance between the first polarity main gate and the second polarity main gate is constant, so as to ensure the collection capability of the fine gate on carriers, and further ensure the battery efficiency of the back contact battery.

In one implementation, the back contact battery further includes: and the bonding pads are arranged on the main grid at intervals along the second direction. When the length of the first polarity fine grid is larger than that of the second polarity additional fine grid, the distance between the free end of the first polarity fine grid and the second polarity main grid which is opposite in polarity and is adjacently arranged is larger than the width of the bonding pad, and/or when the length of the second polarity fine grid is larger than that of the first polarity additional fine grid, the distance between the free end of the second polarity fine grid and the first polarity main grid which is opposite in polarity and adjacently arranged is larger than the width of the bonding pad, and the width direction of the bonding pad is consistent with the first direction.

Under the condition of adopting the technical scheme, the probability that the bonding pad or the bonding belt connects the first polarity fine grid and the second polarity main grid which is opposite to the first polarity fine grid and is adjacently arranged can be reduced or eliminated, and the risk of short circuit of the back contact battery is further reduced or eliminated. Similarly, the probability that the bonding pad or the bonding tape connects the second-polarity fine grid and the first-polarity main grid which is opposite to and adjacent to the second-polarity fine grid can be reduced or eliminated, and the risk of short circuit of the back contact battery is further reduced or eliminated.

In one implementation, the main grids near the edges of the battery body are provided with first polarity fine grids and first polarity additional fine grids which are spaced along the second direction and have the same polarity alternately only on the side facing the adjacent main grids.

Under the condition of adopting the technical scheme, in the process of actually manufacturing the back contact battery, a bonding pad and a bonding strip are arranged. Since the main grids near the edges of the battery body are only on the side facing the adjacent main grids, the first polarity fine grids and the first polarity additional fine grids which have the same polarity are alternately arranged at intervals along the second direction. At this time, not only the solder strip or the solder pad connected with the main grid near the edge of the battery body can be prevented from being electrically connected with the thin grids of two polarities at the same time, so that the risk of short circuit of the back contact battery is reduced or eliminated. Meanwhile, the method of shortening the length of the thin grid with a certain polarity can be avoided, so that the risk of short circuit of the back contact battery is reduced or eliminated, the collection capacity of the thin grid to carriers is further ensured, and the battery efficiency of the back contact battery is ensured.

In one implementation, the back contact battery is a monolithic back contact battery; or, the back contact cell is a sliced back contact cell.

Under the condition of adopting the technical scheme, the back contact battery can be suitable for different application scenes, and the application range of the back contact battery is enlarged.

In a second aspect, the present utility model also provides a battery string. The battery string comprises a plurality of welding strips and a plurality of back contact batteries which are arranged at intervals and are in the technical scheme, and the welding strips are correspondingly connected with the main grid.

Compared with the prior art, the beneficial effects of the battery string provided by the utility model are the same as those of the back contact battery described in the technical scheme, and the description is omitted here.

In one implementation, when the back contact battery further includes a bonding pad, the bonding ribbon is disposed on the bonding pad along the second direction and covers the main gate. The width of the welding strip is smaller than or equal to that of the welding pad, and the width direction of the welding strip and the width direction of the welding pad are consistent with the first direction.

Under the condition of adopting the technical scheme, the shielding of the welding strip to the battery body can be reduced, the light receiving area of the battery body is increased, and the photoelectric conversion efficiency of the back contact battery is improved. Meanwhile, the probability that the welding strip is simultaneously connected with the first polarity main grid and the second polarity main grid due to the welding strip offset in the actual manufacturing process can be reduced or eliminated, so that the risk of short circuit of the back contact battery is reduced or eliminated.

In one implementation, a ratio of the width of the solder strip to the width of the pad is greater than or equal to 0.5 and less than or equal to 1, where the width direction of the solder strip and the width direction of the pad are both consistent with the first direction.

Under the condition of adopting the technical scheme, the ratio is greater than or equal to 0.5, so that the connection firmness of the welding strip and the bonding pad can be ensured, and the current carrying capacity of the welding strip can be ensured. Further, the ratio is smaller than or equal to 1, so that the raw material consumption for manufacturing the welding strip can be reduced, the raw material cost is saved, shielding of the welding strip to the battery body can be reduced, the light receiving area of the battery body is increased, and the photoelectric conversion efficiency of the back contact battery is improved. In addition, the probability that the welding strip is simultaneously connected with the first polarity main grid and the second polarity main grid due to the welding strip offset in the actual manufacturing process can be reduced or eliminated, so that the risk of short circuit of the back contact battery is reduced or eliminated.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model and do not constitute a limitation on the utility model. In the drawings:

Fig. 1 is a schematic diagram of a battery body, a main gate, a fine gate and a bonding pad according to an embodiment of the present utility model;

FIG. 2 is an enlarged schematic view of a portion of the structure of FIG. 1 according to an embodiment of the present utility model;

FIG. 3 is a schematic enlarged view of a portion of the structure of FIG. 1 according to an embodiment of the present utility model;

FIG. 4 is a schematic view of the structure of a battery body, a main grid, a fine grid, a bonding pad and a bonding pad according to an embodiment of the present utility model;

Fig. 5 is a schematic diagram of a battery body, a main gate, a fine gate, and a bonding pad according to an embodiment of the present utility model.

Reference numerals:

1-a battery body, 2-a main grid, 20-a first polarity main grid,

21-Second polarity main grid, 3-fine grid, 30-first polarity fine grid,

31-Second polarity fine grid, 32-second polarity additional fine grid, 33-first polarity additional fine grid,

4-Bonding pads, 5-bonding strips, 6-cutting lines,

7-First back contact cell, 8-second back contact cell.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the utility model is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise. The meaning of "a number" is one or more than one unless specifically defined otherwise.

In the description of the present utility model, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc., are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In combination with the background art section, in addition to the above technical problems, there are also the following problems:

Because the shrinkage factor of the insulating glue is greater than that of the battery body, if the printed insulating glue is too thick, the shrinkage speed of the insulating glue is greater than that of the battery body in the later drying process. At this time, the battery body can be crooked towards the one side that has insulating glue, and then leads to later stage welding location inaccuracy, influences the quality of back contact battery. Further, the greater the thickness of the fine grid, the more insulating paste is printed on both ends of the fine grid. But tends to agglomerate to form bulges during the printing process. At this time, when bonding the bonding pad or the bonding tape, the bump may puncture the film layer formed by the insulating adhesive, so that the bonding pad or the bonding tape is connected with the fine grid. Based on this, the pads or strips are caused to connect the electrodes of both polarities simultaneously, causing the back contact cell to short.

In order to solve the technical problems described above, in a first aspect, an embodiment of the present utility model provides a back contact battery. Referring to fig. 1 and 2, the back contact battery includes: a battery body 1, a plurality of main grids 2 and a plurality of fine grids 3 formed on a backlight surface provided in the battery body 1. The main gate 2 includes a plurality of first polarity main gates 20 and a plurality of second polarity main gates 21, the first polarity main gates 20 and the second polarity main gates 21 extending in a second direction B and being alternately arranged at intervals in a first direction a, the first direction a being different from the second direction B. The fine grid 3 includes a plurality of first polarity fine grids 30 and a plurality of second polarity fine grids 31, the first polarity fine grids 30 and the second polarity fine grids 31 extending in the first direction a, being alternately arranged at intervals in the second direction B, and being alternately arranged in the second direction B. The first polarity fine gate 30 is connected to the first polarity main gate 20, and the second polarity fine gate 31 is connected to the second polarity main gate 21. Wherein between the free end of at least one first polarity fine gate 30 and the second polarity main gate 21 there is included a second polarity additional fine gate 32 extending in the first direction a and connected only to the second polarity main gate 21. And/or, a first polarity additional fine gate 33 extending in the first direction a and connected only to the first polarity main gate 20 is included between the free end of the at least one second polarity fine gate 31 and the first polarity main gate 20.

The first direction and the second direction may be any two directions that are parallel to the surface of the battery body and different from each other. Preferably, referring to fig. 1, the first direction a and the second direction B are orthogonal.

Referring to fig. 1 to 4, as can be seen from the above description, in the back contact battery provided in the embodiment of the present utility model, the length of the first polarity fine grid 30 (and/or the length of the second polarity fine grid 31) is reduced compared to the length of the first polarity fine grid (and/or the length of the second polarity fine grid) in the prior art along the first direction a. At this time, the distance between the first polarity main grid 20 and the free end of the second polarity fine grid 31 (and/or the distance between the second polarity main grid 21 and the free end of the first polarity fine grid 30) is increased. Based on this, when the solder strip 5 is correspondingly connected to the first polarity main grid 20, the distance between the solder strip 5 and the free end of the second polarity fine grid 31 (i.e., the soldering window) is increased compared with the prior art, so that the probability that the solder strip 5 connects the first polarity main grid 20 and the second polarity main grid 21 simultaneously can be reduced or eliminated, and the risk of short circuit of the back contact battery can be reduced or eliminated. At this time, compared with the prior art, the method can reduce or avoid printing insulating glue on the two ends of the thin grid and the cross-region electrode so as to reduce the manufacturing cost of the back contact battery or the photovoltaic module. It should be understood that the bonding pads 5 are correspondingly connected to the second polarity main grid 21, and will not be described herein. Further, since the back contact battery includes the first polarity addition fine grid 33 and/or the second polarity addition fine grid 32, at this time, compared to the case where only the length of the first polarity fine grid 30 and/or the length of the second polarity fine grid 31 is shortened, but the first polarity addition fine grid 33 and/or the second polarity addition fine grid 32 is not increased, the capability of collecting carriers by the fine grid can be improved, and thus the battery efficiency of the back contact battery can be improved.

In addition, as can be seen from the foregoing description, due to the back contact battery provided by the embodiment of the utility model, the printing of insulating glue on two ends of the thin grid can be reduced or avoided. At this time, the probability of deformation of the bending of the battery body can be reduced or eliminated, the accuracy of welding positioning is improved, and the welding quality and the through yield of the back contact battery are improved. Meanwhile, the probability of bulging to puncture a film layer formed by insulating glue can be reduced or eliminated, and the short circuit of the back contact battery is reduced or avoided. It should be appreciated that the back contact cell described above may be a P-type back contact cell or an N-type back contact cell.

As a possible implementation manner, the material for manufacturing the first polarity main gate includes but is not limited to silver, and the material for manufacturing the second polarity main gate includes but is not limited to aluminum.

As one possible implementation, referring to fig. 1 to 4, when the length L1 of the first polarity fine grid 30 is greater than the length L2 of the second polarity additional fine grid 32, the ratio of the length L2 of the second polarity additional fine grid 32 to the maximum width W1 of the second polarity main grid 21 to which the second polarity additional fine grid 32 is correspondingly connected is greater than or equal to 0.5 and less than or equal to 3; the longitudinal direction of the second polarity additional fine gate 32 and the width direction of the second polarity main gate 21 are both identical to the first direction a. For example, the ratio may be 0.5, 0.7, 1, 1.7, 2, 2.7, or 3, etc.

Under the condition of adopting the technical scheme, because the ratio is greater than or equal to 0.5, the distance between the welding strip 5 or the welding pad 4 and the free end of the first polarity fine grid 30 can meet the actual requirement at the moment, so that when the welding strip 5 or the welding pad 4 is correspondingly connected with the second polarity main grid 21, the probability of simultaneously connecting the welding strip 5 or the welding pad 4 with the first polarity main grid 20 and the second polarity main grid 21 can be reduced or eliminated, and the risk of short circuit of the back contact battery is further reduced or eliminated. Further, since the ratio is less than or equal to 3, the loss of the effective PN junction area of the second polarity additional thin gate region correspondingly connected with the second polarity main gate can be reduced or avoided. That is, the collection capability of all the fine gates included in the back contact battery to carriers can be improved, and the collection efficiency of current can be improved.

As one possible implementation, referring to fig. 1 to 4, when the length L3 of the second polarity fine grid 31 is greater than the length L4 of the first polarity additional fine grid 33, the ratio of the length L4 of the first polarity additional fine grid 33 to the maximum width of the first polarity main grid 20 correspondingly connected to the first polarity additional fine grid 33 is greater than or equal to 0.5 and less than or equal to 3; the longitudinal direction of the first polarity additional fine gate 33 and the width direction of the first polarity main gate 20 are both identical to the first direction a. For example, the ratio may be 0.5, 0.7, 1, 1.7, 2, 2.7, or 3, etc.

Under the condition of adopting the technical scheme, because the ratio is greater than or equal to 0.5, the distance between the welding strip 5 or the welding pad 4 and the free end of the second polarity fine grid 31 can meet the actual requirement at the moment, so that when the welding strip 5 or the welding pad 4 is correspondingly connected with the first polarity main grid 20, the probability of simultaneously connecting the welding strip 5 or the welding pad 4 with the first polarity main grid 20 and the second polarity main grid 21 can be reduced or eliminated, and the risk of short circuit of the back contact battery is further reduced or eliminated. Further, since the ratio is less than or equal to 3, the loss of the effective PN junction area of the first polarity additional thin gate region correspondingly connected with the first polarity main gate can be reduced or avoided. That is, the collection capability of all the fine gates included in the back contact battery to carriers can be improved, and the collection efficiency of current can be improved.

As one possible implementation, referring to fig. 1 to 4, when the length L1 of the first polarity fine grating 30 is greater than the length L2 of the second polarity additional fine grating 32, the length L2 of the second polarity additional fine grating 32 is greater than or equal to 0.1mm and less than or equal to 5mm. The longitudinal direction of the first polarity fine grid 30 and the longitudinal direction of the second polarity additional fine grid 32 are both identical to the first direction a. For example, the length of the second polarity additional fine grid 32 may be 0.1mm, 0.5mm, 0.7mm, 1mm, 1.7mm, 2mm, 2.7mm, 3mm, 5mm, or the like.

Since the length of the second polarity additional fine grid 32 is greater than or equal to 0.1mm, the distance between the bonding strap 5 or the bonding pad 4 and the free end of the first polarity fine grid 30 can meet the practical requirement, so that when the bonding strap 5 or the bonding pad 4 is correspondingly connected with the second polarity main grid 21, the probability of simultaneously connecting the first polarity main grid 20 and the second polarity main grid 21 by the bonding strap 5 or the bonding pad 4 can be reduced or eliminated, and the risk of short circuit of the back contact battery is further reduced or eliminated. Further, since the length of the second polarity additional fine gate 32 is less than or equal to 5mm, the loss of the effective PN junction area of the second polarity additional fine gate region correspondingly connected to the second polarity main gate can be reduced or avoided at this time. That is, the collection capability of all the fine gates included in the back contact battery to carriers can be improved, and the collection efficiency of current can be improved.

As one possible implementation, referring to fig. 1 to 4, when the length L3 of the second polarity fine grid 31 is greater than the length L4 of the first polarity additional fine grid 33, the length L4 of the first polarity additional fine grid 33 is greater than or equal to 0.1mm and less than or equal to 5mm. The longitudinal direction of the second polarity fine grid 31 and the longitudinal direction of the first polarity additional fine grid 33 are identical to the first direction a. For example, the length of the first polarity additional fine grid 33 may be 0.1mm, 0.5mm, 0.7mm, 1mm, 1.7mm, 2mm, 2.7mm, 3mm, 5mm, or the like.

Under the above technical scheme, since the length of the first polarity additional fine grid 33 is greater than or equal to 0.1mm, the distance between the bonding strap 5 or the bonding pad 4 and the free end of the second polarity fine grid 31 can meet the practical requirement at this time, so as to reduce or eliminate the probability of connecting the bonding strap 5 or the bonding pad 4 with the first polarity main grid 20 and the second polarity main grid 21 at the same time when the bonding strap 5 or the bonding pad 4 is correspondingly connected with the first polarity main grid 20, thereby reducing or eliminating the risk of shorting the back contact battery. Further, since the length of the first polarity additional fine gate 33 is less than or equal to 5mm, a loss of the effective PN junction area of the first polarity additional fine gate region correspondingly connected to the first polarity main gate can be reduced or avoided at this time. That is, the collection capability of all the fine gates included in the back contact battery to carriers can be improved, and the collection efficiency of current can be improved.

As one possible implementation, referring to fig. 1 to 4, a space L5 is provided between the free end of the first polarity fine grid 30 and the free end of the second polarity additional fine grid 32 adjacent to the first polarity fine grid 30, where the space L5 is greater than 0 micron and less than or equal to 100 microns. For example, the pitch L5 may be 1 micron, 10 microns, 20 microns, 30 microns, 40 microns, 50 microns, 60 microns, 70 microns, 80 microns, 90 microns, 100 microns, or the like.

Since the pitch is greater than 0 μm, the connection of the first polarity fine grid 30 and the second polarity fine grid 31 can be avoided at this time to avoid shorting of the back contact cell. Further, since the pitch is less than or equal to 100 μm, it is possible to avoid the occurrence of the situation that the sum of the lengths of the first polarity fine gate 30 and the second polarity additional fine gate 32 is too small due to the excessively large pitch size when the distance between the first polarity main gate 20 and the second polarity main gate 21 is constant, so as to ensure the collection capability of the fine gates for carriers, and thus, the cell efficiency of the back contact cell.

As a possible implementation manner, referring to fig. 1 to 4, the above-mentioned back contact battery further includes: the pads 4, the plurality of pads 4 are disposed on the main gate at intervals along the second direction B. When the length L1 of the first polarity fine gate 30 is greater than the length L2 of the second polarity additional fine gate 32, the distance L6 between the free end of the first polarity fine gate 30 and the second polarity main gate 21 disposed adjacently and opposite in polarity is greater than the width W2 of the pad 4, and/or when the length of the second polarity fine gate is greater than the length of the first polarity additional fine gate, the distance between the free end of the second polarity fine gate and the first polarity main gate disposed adjacently and opposite in polarity is greater than the width of the pad, and the width direction of the pad 4 coincides with the first direction a.

Under the condition of adopting the technical scheme, the probability that the bonding pad 4 or the bonding tape connects the first polarity fine grid 30 and the second polarity main grid 21 which is opposite in polarity to the first polarity fine grid 30 and is adjacently arranged can be reduced or eliminated, and the risk of short circuit of the back contact battery is further reduced or eliminated. Similarly, the probability that the bonding pad or the bonding tape connects the second-polarity fine grid and the first-polarity main grid which is opposite to and adjacent to the second-polarity fine grid can be reduced or eliminated, and the risk of short circuit of the back contact battery is further reduced or eliminated.

The size, shape, etc. of the pad 4 may be set according to practical situations, and are not particularly limited herein.

As a possible implementation, referring to fig. 1, the width of the first polarity main gate 20 gradually decreases in a direction away from the pad 4, centering on each pad 4, and the width direction of the first polarity main gate 20 coincides with the first direction a.

As can be seen from the foregoing description, since the first polarity main grid 20 is mainly made of silver, the unit price of silver is high. When the gradual change shape is adopted, compared with the width of the first polarity main grid 20 at each position which is equal to the width of the connecting position with the bonding pad 4, the consumption of silver can be reduced, and the raw material cost of the first polarity main grid 20 is saved. Further, since the current density is large near the pad 4, the width of the first polarity main gate 20 at the junction with the pad 4 is wider to secure the conductive performance. The current density is smaller at a position distant from the pad 4, and thus the width of the first polarity main gate 20 at the connection with the pad 4 can be relatively reduced.

The gradual change shape may be, for example, a triangle, a trapezoid, or a shape formed by a straight line and a curved line.

It should be noted that the above "maximum width of the first polarity main grid correspondingly connected to the first polarity additional fine grid" means: width of the first polarity main gate 20 at the overlapping position with the pad 4. That is, the position of the first polarity main gate 20 overlapping the pad 4 is the position of the first polarity main gate 20 where the width is largest.

As a possible implementation, referring to fig. 3, the second polarity main gate includes a main gate connection line and a main gate connection frame, and the pad is connected to the main gate connection frame. The aforementioned "maximum width W1 of the second polarity main gate 21 to which the second polarity additional fine gate 32 is correspondingly connected" refers to the width of the main gate connecting line (i.e., W1 identified in fig. 3), not the width of the main gate connecting frame. Further, the widths of the main gate connection lines are completely equal or substantially equal throughout.

As a possible implementation, referring to fig. 1 to 5, the main grids near the edge of the battery body 1 are provided with first polarity fine grids 30 and first polarity additional fine grids 33 spaced and alternately arranged along the second direction B on only one side facing the adjacent main grid.

In the actual manufacturing process of the back contact cell, the pads 4 and the pads 5 are provided. Since the main grids near the edges of the battery body 1 are provided with the first polarity fine grids 30 and the first polarity additional fine grids 33 spaced and alternately arranged in the second direction B on only one side facing the adjacent main grids. At this time, not only the bonding tape 5 or the bonding pad 4 connected to the main grid near the edge of the battery body 1 can be prevented from being electrically connected to the thin grids of both polarities at the same time, so that the risk of shorting the back contact battery is reduced or eliminated. Meanwhile, the method of shortening the length of the thin grid with a certain polarity can be avoided, so that the risk of short circuit of the back contact battery is reduced or eliminated, the collection capacity of the thin grid to carriers is further ensured, and the battery efficiency of the back contact battery is ensured.

As one possible implementation, referring to fig. 5, the back contact cell is a one-piece back contact cell; or, the back contact cell is a sliced back contact cell.

Under the condition of adopting the technical scheme, the back contact battery can be suitable for different application scenes, and the application range of the back contact battery is enlarged.

For example, referring to fig. 5, the back contact cell is a sliced back contact cell, and the sliced back contact cell is sliced into two cells along the cutting line 6. For convenience of description, two battery pieces formed after cutting are defined as a first back contact battery 7 and a second back contact battery 8, respectively. In the second direction B, the second polarity main grid 21 of the first back contact cell 7 is directly opposite to the first polarity main grid 20 of the second back contact cell 8.

In a second aspect, the embodiment of the utility model further provides a battery string. The battery string comprises a plurality of welding strips and a plurality of back contact batteries which are arranged at intervals and are in the technical scheme, and the welding strips are correspondingly connected with the main grid.

The beneficial effects of the battery string provided by the embodiment of the utility model are the same as those of the back contact battery described in the technical scheme, and are not described in detail herein.

As a possible implementation, referring to fig. 1 to 4, when the back contact battery further includes the pad 4, the bonding tape 5 is disposed on the pad 4 along the second direction B and covers the main gate. The width W3 of the land 5 is smaller than or equal to the width W2 of the pad 4, and both the width direction of the land 5 and the width direction of the pad 4 coincide with the first direction a.

At this time, shielding of the battery body 1 by the solder strip 5 can be reduced, the light receiving area of the battery body 1 can be increased, and the photoelectric conversion efficiency of the back contact battery can be improved. Meanwhile, the probability that the welding strip 5 is connected with the first polarity main grid 20 and the second polarity main grid 21 simultaneously due to the deviation of the welding strip 5 in the actual manufacturing process can be reduced or eliminated, so that the risk of short circuit of the back contact battery is reduced or eliminated.

As a possible implementation manner, referring to fig. 1 to 4, the ratio of the width W3 of the solder strip 5 to the width W2 of the pad 4 is greater than or equal to 0.5 and less than or equal to 1, and the width direction of the solder strip 5 and the width direction of the pad 4 are both consistent with the first direction a. For example, the ratio may be 0.5, 0.65, 0.75, 0.8, 0.85, 0.9, 1, or the like.

Because the ratio is greater than or equal to 0.5, not only can the connection firmness of the welding strip 5 and the bonding pad 4 be ensured, but also the current carrying capacity of the welding strip 5 can be ensured. Further, the ratio is smaller than or equal to 1, so that the raw material consumption for manufacturing the welding strip 5 can be reduced, the raw material cost is saved, shielding of the welding strip 5 to the battery body 1 can be reduced, the light receiving area of the battery body 1 is increased, and the photoelectric conversion efficiency of the back contact battery is improved. In addition, the probability of the solder strip 5 simultaneously connecting the first polarity main grid 20 and the second polarity main grid 21 due to the offset of the solder strip 5 in the actual manufacturing process can be reduced or eliminated, so that the risk of short circuit of the back contact battery is reduced or eliminated.

As a possible implementation, the width of the solder strip is smaller than or equal to the width of the main grid, and the width direction of the solder strip and the width direction of the main grid are consistent with the first direction.

As a possible implementation, the width of the welding strip is smaller than 1.5mm, for example, the welding strip may be a cylindrical welding wire, and the diameter of the welding wire is 500um.

In the description of the above embodiments, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is merely illustrative of the present utility model, and the present utility model is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the protection scope of the claims.

Claims (10)

1. A back contact battery, comprising:

a battery body, a plurality of main grids and a plurality of fine grids formed on a backlight surface of the battery body;

The main grids comprise a plurality of first polarity main grids and a plurality of second polarity main grids, wherein the first polarity main grids and the second polarity main grids extend along a second direction and are alternately arranged at intervals along a first direction; the first direction is different from the second direction;

The fine grid comprises a plurality of first polarity fine grids and a plurality of second polarity fine grids; the first polarity fine grid and the second polarity fine grid extend along a first direction, are alternately arranged at intervals along a second direction, and are arranged in a crossing manner along the second direction; the first polarity fine grid is connected with the first polarity main grid, and the second polarity fine grid is connected with the second polarity main grid;

Wherein a second polarity additional fine gate extending in a first direction and connected only to the second polarity main gate is included between the free end of at least one first polarity fine gate and the second polarity main gate; and/or including a first polarity additional fine gate extending in a first direction between a free end of the at least one second polarity fine gate and the first polarity main gate and connected only to the first polarity main gate.

2. The back contact battery of claim 1, wherein when the length of the first polarity fine grid is greater than the length of the second polarity additional fine grid, the ratio of the length of the second polarity additional fine grid to the maximum width of the second polarity main grid to which the second polarity additional fine grid is correspondingly connected is greater than or equal to 0.5 and less than or equal to 3; the length direction of the second polarity additional thin grid and the width direction of the second polarity main grid are consistent with the first direction; and/or the number of the groups of groups,

When the length of the second polarity fine grid is larger than that of the first polarity additional fine grid, the ratio of the length of the first polarity additional fine grid to the maximum width of the first polarity main grid correspondingly connected with the first polarity additional fine grid is larger than or equal to 0.5 and smaller than or equal to 3; the length direction of the first polarity additional fine grid and the width direction of the first polarity main grid are consistent with the first direction.

3. The back contact battery of claim 1, wherein when the length of the first polarity fine grid is greater than the length of the second polarity additional fine grid, the length of the second polarity additional fine grid is greater than or equal to 0.1mm and less than or equal to 5mm; the length direction of the first polarity fine grid and the length direction of the second polarity additional fine grid are consistent with the first direction; and/or the number of the groups of groups,

When the length of the second polarity fine grid is greater than that of the first polarity additional fine grid, the length of the first polarity additional fine grid is greater than or equal to 0.1mm and less than or equal to 5mm; the length direction of the second polarity fine grid and the length direction of the first polarity additional fine grid are consistent with the first direction.

4. The back contact battery of claim 1, wherein the free ends of the first polarity fine bars and the free ends of the second polarity additional fine bars adjacent to the first polarity fine bars have a spacing therebetween, the spacing being greater than 0 microns and less than or equal to 100 microns.

5. The back contact battery of claim 1, wherein the back contact battery further comprises:

The bonding pads are arranged on the main grid at intervals along the second direction;

When the length of the first polarity fine grid is larger than that of the second polarity additional fine grid, the free end of the first polarity fine grid is opposite to the polarity, and the interval between the adjacent second polarity main grids is larger than the width of the bonding pad; and/or when the length of the second polarity fine grid is greater than that of the first polarity additional fine grid, the free end of the second polarity fine grid is opposite to the polarity and the interval between the adjacent first polarity main grids is greater than the width of the bonding pad; the width direction of the bonding pad is consistent with the first direction.

6. The back contact battery of claim 1, wherein the main grids near the edges of the battery body are provided with the first polarity fine grids and the first polarity additional fine grids which are spaced and alternately arranged in the second direction only on a side facing the adjacent main grids.

7. The back contact battery of claim 1, wherein the back contact battery is a one-piece back contact battery; or, the back contact cell is a sliced back contact cell.

8. A battery string comprising a plurality of solder strips and a plurality of spaced apart back contact batteries according to any one of claims 1 to 7;

the welding strip is correspondingly connected with the main grid.

9. The battery string of claim 8, wherein when the back contact battery further comprises a bonding pad, the bonding strap is disposed on the bonding pad along the second direction and covers the main grid; the width of the welding strip is smaller than or equal to the width of the welding pad; the width direction of the solder strip and the width direction of the bonding pad are consistent with the first direction.

10. The battery string of claim 9, wherein a ratio of a width of the solder strip to a width of the solder pad is greater than or equal to 0.5 and less than or equal to 1.