Back contact battery and photovoltaic module

Abstract

The invention discloses a back contact battery and a photovoltaic module. Comprising a substrate; the plurality of first current collection grid lines and the plurality of second current collection grid lines are alternately arranged along the first direction and extend along the second direction; the plurality of electric combination unit groups are arranged at equal intervals along the second direction, each electric combination unit group comprises a first electric combination unit and a second electric combination unit which extend along the first direction and are sequentially arranged at intervals along the second direction, and the first electric combination unit and the second electric combination unit are respectively connected with the first current collection grid line and the second current collection grid line; in the second direction, the distance between the first electric combination unit and the second electric combination unit in one electric combination unit group is smaller than the distance between the first electric combination unit in the electric combination unit group and the second electric combination unit in the adjacent electric combination unit group, the width of the first electric combination unit is M1, the width of the second electric combination unit is M2, and the width of the first electric combination unit is M1; distance D1, # imgabs0 # between an extension center line of a first electrical bonding unit and an extension center line of a second electrical bonding unit in each group of electrical bonding units

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a back contact cell and a photovoltaic module. Background Art

[0002] A back-contact cell is a cell in which both the emitter and base contact electrodes are placed on the back side of the cell (non-light-receiving side or non-front side). The light-receiving side or front side of the cell is not blocked by any metal electrode, thereby effectively increasing the short-circuit current of the cell. At the same time, the back side can allow wider metal grid lines to reduce the series resistance and thus increase the fill factor.

[0003] For back-contact cells, the electrode structure is the core technology of the cell. Reasonable electrode patterns can better bring out the technical advantages of back-contact cells. Existing back-contact cells collect photocurrent through the interdigitated fine grids in the back PN region, and converge the collected current through the back PN main grid. How to optimize the electrode layout and improve the current collection efficiency has become a problem that technicians in this field need to solve urgently. Summary of the invention

[0004] The object of the present invention is to provide a back contact cell and a photovoltaic module to optimize the electrode arrangement and improve the current collection efficiency.

[0005] In a first aspect, the present invention provides a back contact battery, comprising:

[0006] a substrate having opposing first and second surfaces;

[0007] A plurality of first collector grid lines and a plurality of second collector grid lines, the first collector grid lines and the second collector grid lines are alternately arranged on the first surface along a first direction, the first collector grid lines and the second collector grid lines extend along a second direction, the first collector grid lines and the second collector grid lines have opposite polarities, and the first direction and the second direction intersect;

[0008] A plurality of electrical combination unit groups are arranged at equal intervals on the first surface along the second direction, each electrical combination unit group includes a first electrical combination unit and a second electrical combination unit which are arranged in sequence along the second direction, the first electrical combination unit and the second electrical combination unit both extend along the first direction, the first electrical combination unit is connected to the first collector grid line, and the second electrical combination unit is connected to the second collector grid line;

[0009] Wherein, in the second direction, the distance between the first electrical combination unit and the second electrical combination unit in one group of the electrical combination unit groups is smaller than the distance between the first electrical combination unit in the group of the electrical combination unit groups and the second electrical combination unit in the adjacent group of the electrical combination unit groups, the width of the first electrical combination unit is M1, the width of the second electrical combination unit is M2, the distance between the extended center line of the first electrical combination unit and the extended center line of the second electrical combination unit in each group of the electrical combination unit groups is D1,

[0010]

[0011] When the above technical solution is adopted, a first collector grid line and a second collector grid line with opposite polarities arranged alternately along a first direction are provided on the first surface of the back contact battery, and a first electrical combination unit and a second electrical combination unit arranged alternately along a second direction are provided, the first electrical combination unit is connected to the first collector grid line, and the second electrical combination unit is connected to the second collector grid line, the current of the back contact battery is collected through the first collector grid line and the second collector grid line, the current of the first collector grid line is collected through the first electrical combination unit and exported to the interconnection member, and the current of the second collector grid line is collected through the second electrical combination unit and exported to the interconnection member, wherein a first electrical combination unit and a second electrical combination unit that are relatively close to each other form a group of electrical combination unit groups, and multiple groups of electrical combination unit groups are arranged at equal intervals in the second direction. Since both the first electrical combination unit and the second electrical combination unit have a width, and considering the insulating isolation distance between the first electrical combination unit and the second electrical combination unit with opposite polarities, the distance D1 between the extended center line of the first electrical combination unit and the extended center line of the second electrical combination unit in each group of electrical combination units needs to be greater than 10μm after subtracting half of the width of the first electrical combination unit and then subtracting half of the width of the second electrical combination unit, so as to ensure that the first electrical combination unit and the second electrical combination unit in each group of electrical combination units are as close as possible without contact and the insulating distance is ensured. By arranging the first electrical combination unit and the second electrical combination unit as close as possible, the distribution of the positive and negative charge collection areas is changed to better collect current and improve the current collection efficiency.

[0012] In some possible implementations, Further considering that the first electrical combination unit and the second electrical combination unit may be offset during printing, D1 needs to be greater than 150μm and not more than 600μm after subtracting half of the width of the first electrical combination unit and then half of the width of the second electrical combination unit, so as to avoid the spacing between the first electrical combination unit and the second electrical combination unit being too large, which is not conducive to current collection.

[0013] In some possible implementations, the distance from the extended center line of the first electrical combination unit located at the outermost side of the back contact battery to the end of the adjacent first collector grid line is greater than Alternatively, the distance from the extended center line of the second electrical combination unit located at the outermost side of the back contact cell to the end of the adjacent second collector grid line is greater than Since both the first electrical combination unit and the second electrical combination unit have widths, considering that the first electrical combination unit located at the edge cannot exceed the end of the first collector grid line, and the second electrical combination unit located at the edge cannot exceed the end of the second collector grid line, it is convenient to connect the first electrical combination unit and the second electrical combination unit with the interconnection member, and avoid the risk of fragmentation caused by connecting the interconnection member at the edge of the back contact battery, therefore, D2 and D2' are greater than D3 and D6 are greater than

[0014] In some possible implementations, the distance D2 from the extended center line of the first electrical combination unit located at the outermost side of the back contact battery to the end of the adjacent first collector grid line satisfies: 1300μm<D1≤D2. Since the minimum width of the first electrical combination unit and the second electrical combination unit is 1000μm, considering that the insulation isolation distance between the first electrical combination unit and the second electrical combination unit with opposite polarities is 200μm, considering that the first electrical combination unit and the second electrical combination unit may be offset during printing, and the offset distance is 50μm, then D1 needs to be greater than half of the width of the first electrical combination unit, half of the width of the second electrical combination unit, the offset distance of the first electrical combination unit and the second electrical combination unit, and the insulation isolation distance between the first electrical combination unit and the second electrical combination unit, that is, D1>1300μm, and D1 cannot exceed D2, so as to avoid the distance D6 from the extended center line of the second electrical combination unit located at the outermost side of the back contact battery to the end of the adjacent second collector grid line being zero, and the second electrical combination unit being too close to the edge of the back contact battery, which is not conducive to the arrangement of the edge second electrical combination unit, and the risk of fragmentation at the edge of the back contact battery.

[0015] In some possible implementations, the distance between the extended center lines of two adjacent first electrical combination units is D4, and the distance D2 from the extended center line of the outermost first electrical combination unit of the back contact battery to the end of the adjacent first collector grid line satisfies: 1300μm<D2≤D4-D1, or, 2600μm<D2+D1≤D4. In this way, by reasonably setting the distance D4 between the extended center lines of two adjacent first electrical combination units and the distance D2 from the extended center line of the outermost first electrical combination unit to the end of the adjacent first collector grid line, as well as the distance D1 between the first electrical combination unit and the second electrical combination unit in each group of electrical combination units, it is possible to improve the current collection efficiency, avoid short circuits, and reduce the risk of fragments at the edge of the back contact battery.

[0016] In some possible implementations, the distances from the extended center lines of the two outermost first electrical combination units to the ends of the first collector grid lines adjacent to each other are both D2, the distance between the extended center lines of the two adjacent first electrical combination units is D4, and the ratio of D2 to D4 satisfies:

[0017] Wherein, X is the length of the back contact battery in the second direction, and Y is the number of the first electrical combination units.

[0018] When adopting the above technical solution, the relationship between the distance D2 from the extended center line of the outermost first electrical combination unit to the end of the adjacent first collecting grid line and the distance D4 between the extended center lines of two adjacent first electrical combination units is determined according to the length of the back contact battery and the number of first electrical combination units, so that the arrangement of the first electrical combination units on the back contact battery is reasonable, which can improve the current collection efficiency, avoid short circuits, and reduce the risk of fragments at the edge of the back contact battery.

[0019] In some possible implementations, in the second direction, ends of the first collector gate line and the second collector gate line are flush;

[0020] The distances from the extended center lines of the two outermost first electrical combination units to the ends of the first collector grid lines adjacent to each other are both D2;

[0021] The distance between the extended center lines of two adjacent first electrical combination units is D4;

[0022] The distance between the extended center lines of two adjacent second electrical combination units is D5, and D4=D5;

[0023] The distance from the extended center line of the outermost second electrical combination unit to the end of the adjacent second collector grid line is D3;

[0024] The distance from the extended center line of another second electrical combination unit located at the outermost side to the end of the adjacent second collector grid line is D6, D3>D6;

[0025] The ratio of D3 to D5 satisfies:

[0026] Wherein, X is the length of the back contact battery in the second direction, and Y is the number of the second electrical combination units. When the above technical solution is adopted, the relationship between the distance D6 from the extended center line of the outermost second electrical combination unit to the end of the adjacent second collector grid line and the distance D5 between the extended center lines of two adjacent second electrical combination units is determined according to the length of the back contact battery and the number of the second electrical combination units, so that the second electrical combination units are arranged reasonably on the back contact battery, which can improve the current collection efficiency, avoid short circuits, and reduce the risk of fragments at the edge of the back contact battery.

[0027] In some possible implementations, the first electrical combining unit includes a plurality of first electrical combining portions spaced apart along a first direction, and the first electrical combining portions are connected to the first collector grid line;

[0028] And / or, the second electrical combining unit includes a plurality of second electrical combining portions arranged at intervals along the first direction, and the second electrical combining portions are connected to the second collector grid lines.

[0029] When the above technical solution is adopted, the first electrical combination unit includes a plurality of first electrical combination parts arranged at intervals, and the first collector grid line is connected to the interconnection member through the first electrical combination parts. The second electrical combination unit includes a plurality of second electrical combination parts arranged at intervals, and the second collector grid line is connected to the interconnection member through the second electrical combination parts. Since the first electrical combination unit and the second electrical combination unit have no main grid, the electrode cost is reduced without affecting the current transmission efficiency.

[0030] In some possible implementations, the first electrical combination unit further includes a first busbar line extending along the first direction, and the first busbar line is connected to the first electrical combination portion;

[0031] And / or, the second electrical combining unit further includes a second bus bar line extending along the first direction, and the second bus bar line is connected to the second electrical combining portion.

[0032] When adopting the above technical solution, the first electrical combination unit and the second electrical combination unit also include a main grid, which shortens the current transmission path between the collector grid lines to further improve the current transmission efficiency. The main grid can further collect carriers in the corresponding area of ​​the back contact battery to improve the battery photoelectric conversion efficiency.

[0033] In a second aspect, the present invention further provides a photovoltaic module, comprising:

[0034] A battery string, wherein the battery string is formed by electrically connecting a plurality of back-contact batteries as described in any one of the above items;

[0035] An interconnection member connected to the electrically bonded unit group of the back contact battery;

[0036] and an encapsulation layer covering the surface of the battery string.

[0037] The beneficial effects of the photovoltaic components of the second aspect can be analyzed by referring to the beneficial effects of the first aspect and its various implementations, and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0039] Figure 1 A schematic diagram of the electrode arrangement of a back contact battery provided in an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of the local electrode arrangement structure of a back-contact battery provided in an embodiment of the present invention.

[0041] Figure numerals: 1 is an electrical combination unit group, 11 is a first electrical combination unit, 111 is a first electrical combination part, 12 is a second electrical combination unit, 121 is a second electrical combination part, 2 is a first collector grid line, and 3 is a second collector grid line. DETAILED DESCRIPTION

[0042] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or 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 indirectly connected to the other element.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0045] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0046] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] For back-contact cells, the electrode structure is the core technology of the cell. Reasonable electrode patterns can better bring out the technical advantages of back-contact cells. Existing back-contact cells collect photocurrent through the interdigitated fine grids in the back PN region, and converge the collected current through the back PN main grid. How to optimize the electrode layout and improve the current collection efficiency has become a problem that technicians in this field need to solve urgently.

[0048] First, as Figure 1 and Figure 2As shown, an embodiment of the present invention provides a back-contact battery, including a substrate, a plurality of first collector grid lines 2, a plurality of second collector grid lines 3 and a plurality of electrically coupled unit groups 1; wherein the substrate has a first surface and a second surface opposite to each other, the first surface can be the backlight surface of the substrate, and the second surface can be the light-receiving surface (front surface) of the substrate; the first collector grid lines 2 and the second collector grid lines 3 are alternately arranged on the first surface along a first direction, the first collector grid lines 2 and the second collector grid lines 3 extend along a second direction, the first collector grid lines 2 and the second collector grid lines 3 have opposite polarities, the first collector grid lines 2 and the second collector grid lines 3 are used to collect the current generated by the photovoltaic of the back-contact battery, the first direction and the second direction intersect, and specifically can be Perpendicular to each other; a plurality of groups of electrical combination unit groups 1 are arranged at equal intervals on the first surface along the second direction, each group of electrical combination unit groups 1 includes a first electrical combination unit 11 and a second electrical combination unit 12 which are arranged in sequence along the second direction, the first electrical combination unit 11 and the second electrical combination unit 12 both extend along the first direction, the first electrical combination unit 11 is connected to the first collector grid line 2, the second electrical combination unit 12 is connected to the second collector grid line 3, the first electrical combination unit 11 is used to collect the current collected by the first collector grid line 2, the second electrical combination unit 12 is used to collect the current collected by the second collector grid line 3, the first electrical combination unit 11 and the second electrical combination unit 12 are used to connect to the interconnection member to derive the current.

[0049] Wherein, in the second direction, the distance between the extended center line of the first electrical combination unit 11 and the extended center line of the second electrical combination unit 12 in one electrical combination unit group 1 is smaller than the distance between the extended center line of the first electrical combination unit 11 in the electrical combination unit group 1 and the extended center line of the second electrical combination unit 12 in the adjacent electrical combination unit group 1, the width of the first electrical combination unit 11 is M1, the width of the second electrical combination unit 12 is M2, and the extended center line of the first electrical combination unit 11 in each electrical combination unit group 1 ( Figure 1 The extended center line of the second electrical combination unit 12 ( Figure 1 The distance between the two dotted lines shown in the figure is D1, and the relationship between D1 and M1, M1 is:

[0050] It should be noted that the multiple groups of electrical combination units 1 are arranged at equal intervals along the second direction. It can be understood that the multiple first electrical combination units 11 are arranged at equal intervals along the second direction, and the multiple second electrical combination units 12 are arranged at equal intervals along the second direction. The spacing between two adjacent first electrical combination units 11 is equal to the spacing between two adjacent second electrical combination units 12, and the first electrical combination units 11 and the second electrical combination units 12 are alternately arranged along the second direction.

[0051] In the case of adopting the above technical solution, the first surface of the back contact battery is provided with a first collector grid line 2 and a second collector grid line 3 with opposite polarities arranged alternately along the first direction, and a first electrical combination unit 11 and a second electrical combination unit 12 arranged alternately along the second direction, the first electrical combination unit 11 is connected to the first collector grid line 2, and the second electrical combination unit 12 is connected to the second collector grid line 3, wherein a first electrical combination unit 11 and a second electrical combination unit 12 adjacent and close to each other form a group of electrical combination unit groups 1, and a plurality of groups of electrical combination unit groups 1 are arranged at equal intervals in the second direction. Since the first electrical combination unit 11 and the second electrical combination unit 12 both have a width, and considering the insulation isolation distance between the first electrical combination unit 11 and the second electrical combination unit 12 with opposite polarities, the distance D1 between the extended center line of the first electrical combination unit 11 and the extended center line of the second electrical combination unit 12 in each group of electrical combination unit groups 1 needs to be greater than 10μm after deducting half of the width of the first electrical combination unit 11 and half of the width of the second electrical combination unit 12. Specifically, it can be 11 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, 210μm, 22 0μm, 230μm, 240μm, 250μm, 260μm, 270μm, 280μm, 290μm, 300μm, 310μm, 320μm m, 330μm, 340μm, 350μm, 360μm, 370μm, 380μm, 390μm, 400μm, 410μm, 420μm, 430μm, 440μm, 450μm, 460μm, 470μm, 480μm, 490μm, 500μm, 510μm, 520μm, 530μm, 540μm, 550μm, 560μm, 570μm, 580μm, 590μm, 600μm, etc., to ensure that the first electrical combination unit 11 and the second electrical combination unit 12 in each group of electrical combination units 1 are as close as possible without contact and to ensure the insulation distance, and the first electrical combination unit 11 and the second electrical combination unit 12 are set as close as possible to optimize the distribution of the positive and negative charge collection areas corresponding to the first electrical combination unit 11 and the second electrical combination unit 12, so as to better collect current and improve current collection efficiency.

[0052] In some embodiments, the distance D1 between the extended center line of the first electrical combination unit 11 and the extended center line of the second electrical combination unit 12 in each electrical combination unit group 1 needs to meet the following conditions: Since it is necessary to consider not only the insulation isolation distance between the first electrical combination unit 11 and the second electrical combination unit 12 with opposite polarities, but also the possible offset of the first electrical combination unit 11 and the second electrical combination unit 12 during printing, D1 needs to be greater than 150 μm and less than or equal to 600 μm after subtracting half of the width of the first electrical combination unit 11 and half of the width of the second electrical combination unit 12. Specifically, it can be 151μm, 155μm, 160μm, 165μm, 170μm, 175μm, 180μm, 185μm, 190μm, 195μm, 200μm, 205μm, 210μm, 215μm, 220μm, 225μm, 230μm, 240μm, 250μm, 260μm, 270μm, 280μm, 290μm, 295μm, 300μm, 310μm, 320μm, 330μm, 340μm, 350μm, 360μm, 370μm, 380 The distance between the first and second electrical combination units 11 and 12 is preferably 600 μm, 390 μm, 400 μm, 410 μm, 420 μm, 430 μm, 440 μm, 450 μm, 460 μm, 470 μm, 480 μm, 490 μm, 500 μm, 510 μm, 520 μm, 530 μm, 540 μm, 550 μm, 560 μm, 570 μm, 580 μm, 590 μm, 600 μm, etc., and a sufficient distance is reserved to ensure that the first electrical combination unit 11 and the second electrical combination unit 12 in each electrical combination unit group 1 are as close as possible without contact and the insulation distance is ensured. And it does not exceed 600 μm, so as to avoid that the spacing between the first electrical combination unit 11 and the second electrical combination unit 12 is too large, which is not conducive to the collection of current.

[0053] In some embodiments, the distance D2 from the extended center line of the first electrical combination unit 11 located at the outermost side of the back contact cell to the end of the adjacent first collector grid line 2 is greater than Alternatively, the distance D3 from the extended center line of the second electrical combination unit 12 located at the outermost side of the back contact cell to the end of the adjacent second collector grid line 3 is greater than Since the first electrical combination unit 11 and the second electrical combination unit 12 both have widths, considering that the first electrical combination unit 11 located at the edge cannot exceed the end of the first collector grid line 2, and the second electrical combination unit 12 located at the edge cannot exceed the end of the second collector grid line 3, it is convenient to connect the first electrical combination unit 11 and the second electrical combination unit 12 with the interconnection member, and avoid the risk of fragmentation caused by connecting the interconnection member at the edge of the back contact battery. Therefore, D2 is greater than D3 is greater than

[0054] It should be noted that if Figure 1As shown, the first collector grid line 2 and the second collector grid line 3 have the same extension length in the second direction, and the ends are flush. When the distances from the extended center lines of the two outermost first electrical combination units 11 to the ends of the first collector grid lines 2 adjacent to each other are both D2, that is, the distances are equal, since the second electrical combination unit 12 is staggered with the first electrical combination unit 11 in the second direction, the distance from the extended center line of one of the two outermost second electrical combination units 12 to the end of the adjacent second collector grid line 3 is D3, and the distance from the extended center line of the other second electrical combination unit 12 to the end of the adjacent second collector grid line 3 is D6, D3 and D6 are not equal, and D3 is greater than D6, 2D2=D3+D6. At this time, the smaller distance D6 is also greater than Therefore, the two outermost second electrical combination units 12 do not extend beyond the ends of the second collector grid lines 3 adjacent to each other.

[0055] In addition, when the distance from the extended center line of one first electrical combination unit 11 located at the outermost side of the back contact battery to the end of the adjacent first collector grid line 2 is D2, the distance from the extended center line of another first electrical combination unit 11 located at the outermost side of the back contact battery to the end of the adjacent first collector grid line 2 is D2', wherein D2 and D2' may be equal or unequal, and D2' is also greater than In order to conveniently describe the relationship between the distance from the extended center line of the first electrical combination unit 11 located at the outermost side of the back contact cell to the end of the adjacent first collector grid line 2 and other distances, D2 is used as an example for description below, but D2' also satisfies the same relationship.

[0056] In some embodiments, the distance D2 from the extended center line of the first electrical combination unit 11 located at the outermost side of the back contact battery to the end of the adjacent first collector grid line 2 satisfies: 1300μm<D1<D2. Considering that the width M1 of the first electrical combination unit 11 can range from 1000μm to 1200μm, and the width M2 of the second electrical combination unit 12 can range from 1000μm to 1200μm, the minimum width of the first electrical combination unit 11 and the second electrical combination unit 12 is 1000μm; at the same time, considering that the insulation isolation distance between the first electrical combination unit 11 and the second electrical combination unit 12 with opposite polarities is 0 to 200μm, and considering that the first electrical combination unit 11 and the second electrical combination unit 12 may each be offset during printing, the offset distance is plus or minus 0 to 50μm. Then D1 needs to be greater than the sum of half the width of the first electrical combination unit 11, half the width of the second electrical combination unit 12, the offset distance between the first electrical combination unit 11 and the second electrical combination unit 12, and the insulation isolation distance between the first electrical combination unit 11 and the second electrical combination unit 12, that is, When M1 and M2 both take the minimum value of 1000μm, D1>1300μm, and D1 can specifically be 1301μm, 1310μm, 1320μm, 1330μm, 1340μm, 1350μm, 1360μm, 1370μm, 1380μm, 1390μm, 1400μm, 1410μm, 1420μm , 1430μm, 1440μm, 1450μm, 1460μm, 1470μm, 1480μm, 1490μm, 1500μm, 1510μm, 1520μm, 1530μm, 1540μm, 1550μm, 1560μm, 1570μm, 1580μm, 1590μm, 1600μm, etc.;

[0057] In addition, the first electrical combination unit 11 and the second electrical combination unit 12 in each electrical combination unit group 1 need to be welded to corresponding interconnection parts (such as welding strips) respectively. Since the welding accuracy of the interconnection parts is plus or minus 600 μm, D1>600+600, so D1>1200 μm, but D1 cannot be too large, D1 cannot exceed D2, otherwise D1-D2=D6, such as Figure 1 As shown, D6 will be less than 0. In order to avoid the distance D6 from the extended center line of the second electrical combination unit 12 located at the outermost side of the back contact battery to the end of the adjacent second collector grid line 3 being zero, the second electrical combination unit 12 is too close to the edge of the back contact battery, which is not conducive to the arrangement of the edge second electrical combination unit 12 and creates a risk of fragmentation at the edge of the back contact battery. Therefore, considering D1>1200μm, D1>1300μm, and D1<D2, 1300μm<D1<D2 is obtained.

[0058] For example, D2 can be 1301 μm, 1310 μm, 1320 μm, 1330 μm, 1340 μm, 1350 μm, 1360 μm, 1370 μm, 1380 μm, 1390 μm, 1400 μm, 1410 μm, 1420 μm, 1430 μm, 1440 μm , 1450μm, 1460μm, 1470μm, 1480μm, 1490μm, 1500μm, 1510μm, 1520μm, 1530μm, 1540μm, 1550μm, 1560μm, 1570μm, 1580μm, 1590μm, 1600μm, etc.

[0059] like Figure 1As shown, in some embodiments, the distance between the extended center lines of two adjacent first electrical combination units 11 is D4, and the distance D2 from the extended center line of the first electrical combination unit 11 located at the outermost side of the back contact battery to the end of the adjacent first collector grid line 2 satisfies: 1300μm<D2≤D4-D1, or, 2600μm<D2+D1≤D4. As it has been clearly stated in the above embodiments Because the first electrical combination unit 11 located at the outermost side needs to be welded with the interconnection member, and the welding accuracy is ±600μm, D2>600μm is required, and because the current transmission effect of the first collector grid line 2 is affected by the resistance and transmission distance of the first collector grid line 2, D2≤D4 is required. Combining D2>600μm and D2≤D4, 600<D2≤D4 is obtained, and combining 1300μm<D1<D2 in the above embodiment, 1300μm<D2≤D4-D1 can be obtained, or 2600μm<D2+D1≤D4.

[0060] In this way, by reasonably setting the distance D4 between the extended center lines of two adjacent first electrical combination units 11 and the distance D2 from the extended center line of the outermost first electrical combination unit 11 to the end of the adjacent first collector grid line 2, as well as the distance D1 between the first electrical combination unit 11 and the second electrical combination unit 12 in each group of electrical combination units 1, it is possible to improve the current collection efficiency, avoid short circuits, and reduce the risk of fragmentation at the edge of the back contact battery.

[0061] In some embodiments, the distances from the extended center lines of the two outermost first electrical combination units 11 to the ends of the first collector grid lines 2 adjacent to each other are both D2, and the distance between the extended center lines of the two adjacent first electrical combination units 11 is D4, and the ratio of D2 to D4 satisfies:

[0062] Wherein, X is the length of the back contact battery in the second direction, and Y is the number of the first electrical combining units 11 .

[0063] The calculation process of the ratio of D2 to D4 is as follows:

[0064]

[0065] When D2 takes the minimum value and D4 takes the maximum value, the ratio of D2 to D4 is the smallest. From 1300μm<D2≤D4-D1, it can be seen that the minimum value of D2 is 1300μm, that is, 1.3mm. Substituting it into formula (1), the maximum value of D4 is obtained:

[0066]

[0067] Substituting formula (3) and D2 minimum 1.3 mm into formula (2), we get

[0068] For example, the length X of the back contact battery in the second direction may be 156 mm to 210 mm, and the number Y of the first electrical connection units may be 12 to 24. Substituting X and Y into The minimum ratio of D2 to D4 can be obtained. For example, when X is 210 mm and Y is 12, When X is 210mm and Y is 24, When X is 156mm and Y is 24, When X is 156mm and Y is 12,

[0069] When D2 takes the maximum value and D4 takes the minimum value, the ratio of D2 to D4 is the largest. According to the above 1300μm<D2≤D4-D1, it can be obtained that the maximum value of D2 is D4-D1, then According to 1300μm<D1<D2, when the minimum value of D1 is 1.3mm, then Based on the above, we can get the minimum relationship between the ratio of D2 and D4:

[0070]

[0071] When it is known that the length X of the back contact battery in the second direction can be 156 mm to 210 mm and the number Y of the first electrical connection units can be 12 to 24, substituting into equation (4) the value range of the ratio of D2 to D4 is obtained.

[0072] When the above technical solution is adopted, the relationship between the distance D2 from the extended center line of the outermost first electrical combination unit 11 to the end of the adjacent first collector grid line 2 and the distance D4 between the extended center lines of two adjacent first electrical combination units 11 is determined according to the length X of the back contact battery and the number Y of the first electrical combination units 11, so that the arrangement of the first electrical combination units 11 on the back contact battery is reasonable, which can improve the current collection efficiency, avoid short circuits, and reduce the risk of fragments at the edge of the back contact battery.

[0073] like Figure 1As shown, in some embodiments, in the second direction, the ends of the first collector grid line 2 and the second collector grid line 3 are flush; the distances from the extended center lines of the two outermost first electrical combination units 11 to the ends of the first collector grid lines 2 adjacent to each other are both D2; the distance between the extended center lines of the two adjacent first electrical combination units 11 is D4; the distance between the extended center lines of the two adjacent second electrical combination units 12 is D5, D4=D5; the distance from the extended center line of the outermost second electrical combination unit 12 to the end of the adjacent second collector grid line 3 is D3; the distance from the extended center line of the other outermost second electrical combination unit 12 to the end of the adjacent second collector grid line 3 is D6, D3>D6;

[0074] The ratio of D3 to D5 satisfies:

[0075] Wherein, X is the length of the back contact battery in the second direction, and Y is the number of the second electrical combining units 12 .

[0076] The calculation process of the ratio of D3 to D5 is as follows:

[0077] See also Figure 1 As shown,

[0078] D3=D1+D2 (5);

[0079]

[0080] Substituting formula (1) and formula (5) into formula (6), we get

[0081]

[0082] From the above embodiment, we can see that 2600μm<D2+D1≤D4, 1300μm<D2≤D4-D1. It can be seen that when D2+D1 takes the minimum value of 2600μm and D2 takes the minimum value of 1300μm, the ratio of D3 to D5 is the smallest, that is, In addition, D3 cannot exceed D5, so when the ratio of D3 to D5 is the largest, The ratio of D3 to D5 is obtained as follows:

[0083] When it is known that the length X of the back contact battery in the second direction can be 156 mm to 210 mm and the number Y of the second electrical connection units can be 12 to 24, substituting into equation (8) the value range of the ratio of D3 to D5 is obtained.

[0084] For example, when X is 210mm and Y is 12, When X is 210mm and Y is 24, When X is 156mm and Y is 24, When X is 156mm and Y is 12,

[0085] When adopting the above technical solution, the relationship between the distance D3 from the extended center line of the outermost second electrical combination unit 12 to the end of the adjacent second collector grid line 3 and the distance D5 between the extended center lines of two adjacent second electrical combination units 12 is determined according to the length X of the back contact battery and the number Y of the second electrical combination units 12, so that the arrangement of the second electrical combination units 12 on the back contact battery is reasonable, which can improve the current collection efficiency, avoid short circuits, and reduce the risk of fragments at the edge of the back contact battery.

[0086] like Figure 2 As shown, in some embodiments, the first electrical combination unit 11 includes a plurality of first electrical combination parts 111 arranged at intervals along the first direction, the first electrical combination parts 111 are connected to the first collector grid line 2, and the first electrical combination parts 111 may correspond to the pads on the first collector grid line 2, the terminal lines corresponding to the ends of the first collector grid line 2, or the thickened sections on the first collector grid line 2. The second electrical combination unit 12 includes a plurality of second electrical combination parts 121 arranged at intervals along the first direction, the second electrical combination parts 121 are connected to the second collector grid line 3, and the second electrical combination parts 121 may correspond to the pads on the second collector grid line 3, the terminal lines corresponding to the ends of the second collector grid line 3, or the thickened sections on the second collector grid line 3. The first electrical combination parts 111 and the second electrical combination parts 121 may be electrically connected to the collector grid line and conductively connected to the interconnection parts, such as welding strips.

[0087] When the above technical solution is adopted, the first electrical combination unit 11 includes a plurality of first electrical combination parts 111 arranged at intervals, and the first collector grid line 2 is connected to the interconnection member through the first electrical combination parts 111. The second electrical combination unit 12 includes a plurality of second electrical combination parts 121 arranged at intervals, and the second collector grid line 3 is connected to the interconnection member through the second electrical combination parts 121. Since the first electrical combination unit 11 and the second electrical combination unit 12 have no main grid, the main grid material is saved and the electrode cost is reduced without affecting the current transmission efficiency.

[0088] In some embodiments, the first electrical combination unit 11 includes, in addition to the plurality of first electrical combination portions 111 , a first busbar line extending along a first direction, also referred to as a first main grid, and the first busbar line is connected to the first electrical combination portion 111 ;

[0089] Similarly, in addition to the plurality of second electrical combining portions 121 , the second electrical combining unit 12 further includes a second busbar line extending along the first direction, also called a second main grid, and the second busbar line is connected to the second electrical combining portion 121 .

[0090] When the above technical solution is adopted, the first electrical combination unit 11 and the second electrical combination unit 12 also include a main grid, which shortens the current transmission path between the collector grid lines to further improve the current transmission efficiency. The main grid can further collect carriers in the corresponding area of ​​the back contact battery to improve the battery photoelectric conversion efficiency.

[0091] In a second aspect, an embodiment of the present invention further provides a photovoltaic module, comprising a cell string, an interconnection member and a packaging layer, wherein the cell string is formed by electrically connecting a number of back-contact cells as described in any of the above embodiments; the interconnection member is connected to an electrical connection unit group 1 of the back-contact cells; and the packaging layer covers the surface of the cell string.

[0092] The beneficial effects of the photovoltaic components in the embodiments of the present application can be analyzed by referring to the first aspect and its various implementation methods, which will not be elaborated here.

[0093] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0094] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A back contact battery, characterized in that: include: a substrate having opposing first and second surfaces; A plurality of first collector grid lines and a plurality of second collector grid lines, wherein the first collector grid lines and the second collector grid lines are alternately arranged on the first surface along a first direction, the first collector grid lines and the second collector grid lines extend along a second direction, the first collector grid lines and the second collector grid lines have opposite polarities, and the first direction and the second direction intersect; A plurality of groups of electrical combination units are arranged at equal intervals on the first surface along the second direction, each group of the electrical combination units includes a first electrical combination unit and a second electrical combination unit which are arranged in sequence along the second direction, the first electrical combination unit and the second electrical combination unit both extend along the first direction, the first electrical combination unit is connected to the first collector grid line, and the second electrical combination unit is connected to the second collector grid line; Wherein, in the second direction, the distance between the extended center line of the first electrical combination unit and the extended center line of the second electrical combination unit in a group of the electrical combination unit groups is smaller than the distance between the extended center line of the first electrical combination unit in the group of the electrical combination unit groups and the extended center line of the second electrical combination unit in the adjacent group of the electrical combination unit groups, the width of the first electrical combination unit is M1, the width of the second electrical combination unit is M2, and the distance between the extended center line of the first electrical combination unit and the extended center line of the second electrical combination unit in each group of the electrical combination unit groups is D1, 2. The back contact cell according to claim 1, characterized in that:

3. The back contact cell according to claim 1, characterized in that: The distance between the extended center line of the first electrical combination unit located at the outermost side of the back contact battery and the end of the adjacent first collector grid line is greater than Alternatively, the distance from the extended center line of the second electrical combination unit located at the outermost side of the back contact battery to the end of the adjacent second collector grid line is greater than 4. The back contact cell according to claim 1, characterized in that: A distance D2 from an extended center line of the first electrical combining unit located at the outermost side of the back contact cell to an end of the adjacent first collector grid line satisfies: 1300 μm<D1≤D2.

5. The back contact cell according to claim 1, characterized in that: The distance between the extended center lines of two adjacent first electrical combination units is D4, and the distance D2 from the extended center line of the first electrical combination unit located at the outermost side of the back contact battery to the end of the adjacent first collector grid line satisfies: 1300μm<D2≤D4-D1, or, 2600μm<D2+D1≤D4.

6. The back contact cell according to claim 1, characterized in that: The distances from the extended center lines of the two outermost first electrical combination units to the ends of the first collector grid lines adjacent to each other are both D2, and the distance between the extended center lines of two adjacent first electrical combination units is D4, and the ratio of D2 to D4 satisfies: Wherein, X is the length of the back contact battery in the second direction, and Y is the number of the first electrical combination units.

7. The back contact cell according to claim 1, characterized in that: In the second direction, ends of the first collector grid line and the second collector grid line are flush; The distances from the extended center lines of the two first electrical combination units located at the outermost sides to the ends of the first collector grid lines adjacent to each other are both D2; The distance between the extended center lines of two adjacent first electrical combination units is D4; The distance between the extended center lines of two adjacent second electrical combination units is D5, and D4=D5; The distance from the extended center line of the outermost second electrical combination unit to the end of the adjacent second collector grid line is D3; The distance from the extended center line of another second electrical combination unit located at the outermost side to the end of the adjacent second collector grid line is D6, D3>D6; The ratio of D3 to D5 satisfies: Wherein, X is the length of the back contact battery in the second direction, and Y is the number of the second electrical combination units.

8. The back contact cell according to claim 1, characterized in that: The first electrical combination unit includes a plurality of first electrical combination parts arranged at intervals along the first direction, and the first electrical combination parts are connected to the first collector grid line; And / or, the second electrical combining unit includes a plurality of second electrical combining portions arranged at intervals along the first direction, and the second electrical combining portions are connected to the second collector grid lines.

9. The back contact cell according to claim 8, characterized in that: The first electrical combination unit further includes a first busbar line extending along the first direction, the first busbar line being connected to the first electrical combination portion; And / or, the second electrical combining unit further includes a second bus bar extending along the first direction, and the second bus bar is connected to the second electrical combining portion.

10. A photovoltaic module, characterized in that: include: A battery string, wherein the battery string is formed by electrically connecting a plurality of back-contact batteries according to any one of claims 1 to 9; An interconnection member connected to the electrically coupled unit group of the back contact battery; and a packaging layer covering the surface of the battery string.

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