CN218482252U - Electrode structure, solar cell piece, battery pack and photovoltaic system - Google Patents

Abstract

The utility model is suitable for a solar cell technical field provides an electrode structure, solar wafer, battery pack and photovoltaic system, electrode structure includes the main grid, a plurality of silver electrode and vice grid, the main grid can include along first aluminium main grid line and the second aluminium main grid line that the first direction interval set up, first aluminium main grid line and second aluminium main grid line are connected to the vice grid, a plurality of silver electrode can set up between first aluminium main grid line and second aluminium main grid line, a plurality of silver electrode set up along the second direction interval. The silver electrode can include the body and the protruding a plurality of overlap joint convex parts that establish in the body both sides, and the overlap joint convex part that is located the body both sides overlaps with first aluminium main grid line and second aluminium main grid line respectively. So, set up the main grid into the first aluminium main grid line and the second aluminium main grid line that two intervals set up can effectually avoid appearing the problem of rosin joint when the welding, the body of silver electrode passes through the use that overlap joint convex part and first aluminium main grid line and second aluminium main grid line overlap joint can reduce the silver thick liquid with reduce cost.

Description

Electrode structure, solar cell piece, battery pack and photovoltaic system

Technical Field

The utility model relates to a solar cell technical field especially relates to an electrode structure, solar wafer, battery pack and photovoltaic system.

Background

The electrode structure on the back surface of the PERC solar cell generally comprises an aluminum main grid, a secondary grid and a silver electrode, wherein the secondary grid and the main grid are arranged perpendicular to each other. Meanwhile, the two ends of the silver electrode are usually directly embedded into the aluminum main grid and are lapped with the aluminum main grid, and the silver electrode consumes more silver paste and has higher cost.

SUMMERY OF THE UTILITY MODEL

The utility model provides an electrode structure, solar wafer, battery pack and photovoltaic system aims at solving among the prior art solar wafer and appear rosin joint and silver electrode silver thick liquid in the welding easily and consume more technical problem that leads to the cost higher.

The utility model discloses a realize like this, the embodiment of the utility model provides an in electrode structure be used for solar wafer, electrode structure includes:

the main grid comprises a first aluminum main grid line and a second aluminum main grid line which are arranged at intervals along a first direction and extend along a second direction, and the second direction is crossed with the first direction;

the auxiliary grid is connected with the first aluminum main grid line and the second aluminum main grid line; and

the silver electrodes are arranged between the first aluminum main grid line and the second aluminum main grid line, the silver electrodes are arranged at intervals along the second direction, each silver electrode comprises a body and a plurality of overlapping convex parts arranged on two sides of the body in a protruding mode, the body extends along the second direction, the overlapping convex parts extend along the first direction, the overlapping convex parts are arranged at intervals along the second direction with the same sides, the body is arranged at intervals with the first aluminum main grid line and the second aluminum main grid line, and the overlapping convex parts on two sides of the body are respectively in overlapping joint with the first aluminum main grid line and the second aluminum main grid line.

Further, the distance between two adjacent overlapping convex parts on the same side is 0.4mm-0.8mm.

Further, in the first direction, a ratio of a length of the body to a projection height of the overlapping protrusion is greater than or equal to 2.

Furthermore, the length of the silver electrode in the first direction is 1.2mm-3mm, the length of the body in the first direction is 0.5mm-1.5mm, and the protruding height of the overlapping convex part is 0.35mm-0.75mm.

Furthermore, the plurality of silver electrodes include a first electrode and a second electrode, the first electrode is disposed at the end portions of the first aluminum main grid line and the second aluminum main grid line, the second electrodes are disposed at the middle positions of the first aluminum main grid line and the second aluminum main grid line, and the length of the first electrode is greater than that of the second electrode in the second direction.

Furthermore, in the second direction, the length of the first electrode is 2.8mm-4mm, and the length of the second electrode is 1.8mm-3mm.

Furthermore, the secondary grid comprises a plurality of first secondary grid lines and at least one second secondary grid line, the first secondary grid lines are connected to two sides of the primary grid, and the second secondary grid lines are connected between the first aluminum primary grid lines and the second aluminum primary grid lines and located between two adjacent silver electrodes.

The utility model also provides a solar wafer, solar wafer includes:

a substrate;

the electrode structure of any one of the above, wherein the electrode structure is disposed on the back side of the substrate;

and the welding strip is arranged between the first aluminum main grid line and the second aluminum main grid line and is welded with the plurality of silver electrodes.

The utility model also provides a battery pack, battery pack includes a plurality of foretell solar wafer.

The utility model also provides a photovoltaic system, photovoltaic system includes foretell battery pack.

The utility model discloses the beneficial effect who reaches is: on the one hand, set up the main grid into the first aluminium main grid line and the second aluminium main grid line that two intervals set up and can effectually avoid when the welding because there is the difference in height and the problem of rosin joint easily appearing between main grid and the silver electrode, on the other hand, the body of silver electrode passes through the overlap joint convex part and the overlap joint of first aluminium main grid line and second aluminium main grid line rather than the both ends and the overlap joint of direct whole silver electrode and first aluminium main grid line and second aluminium main grid line, can reduce the use of silver thick liquid so with reduce cost.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

Fig. 1 is a schematic structural diagram of a photovoltaic system provided by the present invention;

fig. 2 is a schematic structural diagram of a battery assembly provided by the present invention;

fig. 3 is a schematic structural diagram of a solar cell provided by the present invention;

fig. 4 is an enlarged schematic view of the solar cell in fig. 3 at IV;

fig. 5 is a schematic structural diagram of a silver electrode in an electrode structure provided by the present invention.

Description of the main element symbols:

the solar cell comprises a photovoltaic system 1000, a cell module 200, a solar cell 100, a substrate 10, an electrode structure 20, a main grid 21, a first aluminum main grid line 211, a second aluminum main grid line 212, a silver electrode 22, a body 221, a lapping convex part 222, a first electrode 223, a second electrode 224, a secondary grid 23, a first aluminum secondary grid line 231 and a second aluminum secondary grid line 232.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. Examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present invention, and should not be construed as limiting the present invention. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the description of the present invention, it is to be understood that the terms "longitudinal", "transverse", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. In order to simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or reference letters in the various examples, which have been repeated for purposes of simplicity and clarity and do not in themselves dictate a relationship between the various embodiments and/or arrangements discussed. In addition, the present disclosure provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.

In the related art, the PERC solar cell generally adopts a ring-shaped design for the aluminum main grid connected to the silver electrode, however, a certain height difference exists between the aluminum main grid and the silver electrode, and this height difference easily causes a problem of cold joint during welding. Meanwhile, the two ends of the silver electrode are usually directly embedded into the aluminum main grid and are lapped with the aluminum main grid, and the silver electrode consumes more silver paste and has higher cost.

The utility model discloses in, set up main grid 21 into the first aluminium main grid line 211 and the second aluminium main grid line 212 that two intervals set up and can effectually avoid when the welding because there is the difference in height between main grid 21 and the silver electrode 22 and the problem of rosin joint appears easily. The body 221 of the silver electrode 22 is lapped with the first aluminum main gate line 211 and the second aluminum main gate line 212 through the lapping convex portion 222 instead of directly lapping the two ends of the whole silver electrode 22 with the first aluminum main gate line 211 and the second aluminum main gate line 212, so that the use of silver paste can be reduced to reduce the cost.

Example one

Referring to fig. 1 and fig. 2, a photovoltaic system 1000 of the present invention may include a battery assembly 200 in an embodiment of the present invention, and the battery assembly 200 in an embodiment of the present invention may include a plurality of solar cells 100 in an embodiment of the present invention.

Referring to fig. 3, a solar cell 100 according to an embodiment of the present invention may include a substrate 10, an electrode structure 20 according to an embodiment of the present invention, and a welding bar (not shown), and the electrode structure 20 may be disposed on a back surface of the substrate 10. The solar cell piece 100 can be a PERC solar cell piece, and the electrode structure 20 in the embodiment of the present invention can be disposed on the back surface of the PERC solar cell piece, i.e. the back electrode structure of the PERC solar cell surface. Taking the PERC solar cell as an example, the substrate 10 may be a silicon wafer with an antireflective coating layer on the front surface and a passivation coating layer on the back surface, and the antireflective coating layer and the passivation coating layer may both be silicon nitride coating layers, or the antireflective coating layer may be a silicon nitride coating layer and the passivation coating layer may be other types of coating layers, which is not limited herein. The embodiment of the present invention provides an electrode structure 20 which can be disposed on the back of the substrate 10 and can run through the passivation film layer and the ohmic contact of the silicon wafer on the back, and simultaneously, the front of the silicon wafer can be disposed with a front electrode running through the antireflective film layer, and the following description will be given by taking the solar cell 100 as the PREC solar cell 100.

Referring to fig. 3 and 4, the electrode structure 20 of the present invention may include a main grid 21, a plurality of silver electrodes 22 and a sub-grid 23, the main grid 21 may include a first aluminum main grid line 211 and a second aluminum main grid line 212 arranged at intervals along a first direction, the first aluminum main grid line 211 and the second aluminum main grid line 212 extend along a second direction, and the second direction crosses the first direction. The sub-gate 23 connects the first and second aluminum bus bars 211 and 212.

The plurality of silver electrodes 22 may be disposed between the first aluminum bus bar 211 and the second aluminum bus bar 212 and electrically connected to the first aluminum bus bar 211 and the second aluminum bus bar 212, and the plurality of silver electrodes 22 are disposed at intervals along the second direction.

The silver electrode 22 may include a body 221 and a plurality of overlapping protrusions 222 protruding from two sides of the body 221, the body 221 extends along the second direction, the overlapping protrusions 222 extend along the first direction, the overlapping protrusions 222 are spaced apart from each other along the second direction, the body 221 is spaced apart from the first aluminum main gate line 211 and the second aluminum main gate line 212, and the overlapping protrusions 222 disposed on two sides of the body 221 are respectively overlapped with the first aluminum main gate line 211 and the second aluminum main gate line 212.

A solder bar may be disposed between the first and second aluminum bus bars 211 and 212 and soldered to the plurality of silver electrodes 22 to realize bus bar output, the solder bar also extending in the second direction.

The utility model discloses a solar wafer 100, among battery pack 200 and the photovoltaic system 1000, electrode structure 20 includes main grid 21, vice grid 23 and a plurality of silver electrode 22, main grid 21 includes first aluminium main grid line 211 and the second aluminium main grid line 212 that sets up along the first direction interval, first aluminium main grid line 211 and the second aluminium main grid line 212 are connected to vice grid 23, silver electrode 22 sets up between first aluminium main grid line 211 and second aluminium main grid line 212, a plurality of silver electrode 22 set up along the second direction interval, silver electrode 22 includes body 221 and the protruding overlap joint convex part 222 of establishing at body 221 both sides, body 221 sets up with first aluminium main grid line 211 and second aluminium main grid line 212 interval, the overlap joint convex part 222 that is located body 221 both sides respectively with first aluminium main grid line 211 and the overlap joint of second aluminium main grid line 212. So, on the one hand, set up the main grid 21 to be the first aluminium main grid line 211 and the second aluminium main grid line 212 that two intervals set up and can effectually avoid when the welding because there is the difference in height between main grid 21 and the silver electrode 22 and the problem of rosin joint appears easily, and on the other hand, the body 221 of silver electrode 22 passes through overlap joint convex part 222 and first aluminium main grid line 211 and the overlap joint of second aluminium main grid line 212 rather than direct whole silver electrode 22's both ends and first aluminium main grid line 211 and the overlap joint of second aluminium main grid line 212, can reduce the use of silver thick liquid so with reduce cost. From another perspective, in the present invention, the body 221 of the silver electrode 22 can be set to be narrow and not directly connected to the first aluminum main gate line 211 and the second aluminum main gate line 212, but the conductive connection is realized by the first aluminum main gate line 211 and the second aluminum main gate line 212 through the overlapping convex portion 222, thereby reducing the usage of silver paste.

Specifically, in the present embodiment of the present invention, the overlapping protrusions 222 on both sides of the body 221 may be symmetrically disposed, that is, the number and the positions of the overlapping protrusions 222 on both sides correspond, and it is understood that, in some embodiments, the overlapping protrusions 222 on both sides of the body 221 may not be disposed in an asymmetric structure, and are not limited herein.

In the embodiment of the present invention, the overlapping protrusion 222 may preferably have a rectangular shape, but the shape of the overlapping protrusion 222 may also be a saw-tooth shape or other shapes, and the shape of the overlapping protrusion 222 is not limited herein,

in the embodiment of the present invention, the plurality of solar cells 100 in the battery assembly 200 can be serially connected or connected in parallel to form a battery string, thereby realizing the serial connection or parallel connection of the current, for example, the solar cells 100 can be serially connected by setting up the welding bars. In some embodiments, the solar cell sheet 100 may be disposed in two upper and lower regions, which may be symmetrically disposed, and the electrode structures 20 are disposed in the two regions, after the solar cell sheet 100 is manufactured, two half cells may be cut along a central line, and then, the two half cells may be connected in series or in parallel to form a cell string, and the cell assembly 200 may include a plurality of cell strings.

It is understood that, in the embodiment of the present invention, the battery assembly 200 may further include a metal frame, a back sheet, a photovoltaic glass, and an adhesive film (not shown). The adhesive film may be attached to the front side and the back side of the solar cell sheet 100, and may be a transparent adhesive with good light transmittance and aging resistance, for example, the adhesive film may be an EVA adhesive film or a POE adhesive film, which may be specifically selected according to actual situations, and is not limited herein.

The photovoltaic glass may be an ultra-white glass having high light transmittance, high transparency, and excellent physical, mechanical, and optical properties, for example, the light transmittance of the ultra-white glass may be more than 80%, which may protect the solar cell 100 without affecting the efficiency of the solar cell 100 as much as possible. Meanwhile, the adhesive film can bond the photovoltaic glass and the solar cell piece 100 together, and the existence of the adhesive film can seal, insulate, prevent water and prevent moisture for the solar cell piece 100.

The back plate can be attached to an adhesive film on the back surface of the solar cell piece 100, the back plate can protect and support the solar cell piece 100, and has reliable insulating property, water resistance and aging resistance, the back plate can be selected in multiple ways, can be generally toughened glass, organic glass, an aluminum alloy TPT composite adhesive film and the like, can be specifically arranged according to specific conditions, and is not limited herein. The whole of the back sheet, the solar cell sheet 100, the adhesive film, and the photovoltaic glass may be disposed on a metal frame, which serves as a main external support structure of the entire cell assembly 200 and may stably support and mount the cell assembly 200, for example, the cell assembly 200 may be mounted at a position where it is required to be mounted through the metal frame.

Further, the utility model discloses in, photovoltaic system 1000 can use in photovoltaic power station, for example ground power station, roof power station, surface of water power station etc. also can use on utilizing solar energy to carry out equipment or the device of electricity generation, for example user solar power supply, solar street lamp, solar car, solar energy building etc.. Of course, it is understood that the application scenario of the photovoltaic system 1000 is not limited thereto, that is, the photovoltaic system 1000 may be applied in all fields requiring solar energy for power generation. Taking a photovoltaic power generation system network as an example, the photovoltaic system 1000 may include a photovoltaic array, a combiner box and an inverter, the photovoltaic array may be an array combination of a plurality of battery assemblies 200, for example, the plurality of battery assemblies 200 may form a plurality of photovoltaic arrays, the photovoltaic array is connected to the combiner box, the combiner box may combine currents generated by the photovoltaic array, and the combined currents are converted into alternating currents required by a utility grid through the inverter and then are connected to the utility grid to realize solar power supply.

Further, in the utility model discloses in, solar wafer 100 can be the rectangle form basically, first direction can be the transverse direction of solar wafer 100, the second direction can be the longitudinal direction of solar wafer 100, both mutually perpendicular, that is to say, first aluminium main grid line 211 and second aluminium main grid line 212 can be followed the longitudinal direction and extended and arranged along the transverse direction, the auxiliary grid 23 then can be followed the transverse direction and extended and first aluminium main grid line 211 and second aluminium main grid line 212 are perpendicular, longitudinal direction interval arrangement can be followed to a plurality of silver electrodes 22, body 221 extends along the longitudinal direction, overlap joint convex part 222 is protruding from the both sides of body 221 along the transverse direction. Of course, it is understood that in other embodiments, the first direction and the second direction may not be the transverse direction and the longitudinal direction of the solar cell sheet 100, for example, both may be the directions of two diagonals of the solar cell sheet 100, and are not limited herein.

In addition, as shown in fig. 3 and 4, it can be understood that, in the solar cell 100, the number of the main grids 21 is plural, and the plural main grids 21 are arranged in parallel at intervals along the first direction, for example, taking the solar cell 100 with the length and the width of 182mm as an example, the number of the main grids 21 may be set to 10, and the interval distance between two adjacent main grids 21 may be set to about 17.3 mm.

Furthermore, in the present invention, the electrode structure 20 may be formed on the back surface of the solar cell 100 by screen printing and sintering, for example, in some embodiments, a plurality of silver electrodes 22 may be printed and sintered on the back surface of the solar cell 100 by screen printing and sintering, and then the main grid 21 and the sub-grid 23 may be formed by screen printing and sintering, it is understood that, in the present invention, the main grid 21 may be formed by screen printing and sintering, and then the sub-grid 23 may be formed by screen printing and sintering, or the main grid 21 and the sub-grid 23 may be formed by screen printing and sintering simultaneously, and particularly, the present invention is not limited thereto.

Example two

Referring to fig. 5, in some embodiments, the distance L1 between two adjacent overlapping protrusions 222 located on the same side may be 0.4mm to 0.8mm.

As such, setting the distance L1 between two adjacent overlapping convex portions 222 to the above range can reduce the use of silver paste as much as possible while ensuring the overlapping stability to save cost.

Specifically, in such an embodiment, a groove is formed between two adjacent overlapping protrusions 222, that is, the width of the groove may be 0.4mm to 0.8mm, and the specific distance between two adjacent overlapping protrusions 222 may be 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, or any value between 0.4mm and 0.8mm, and may preferably be about 0.6mm, and is not limited herein.

EXAMPLE III

In some embodiments, the ratio of the length of the body 221 to the projection height of the shiplap joint protrusion 222 in the first direction is greater than or equal to 2.

Thus, setting the ratio of the length of the body 221 to the protruding height of the overlapping protrusion 222 to be greater than or equal to 2 can ensure the welding performance of the body 221 and the welding strip to avoid poor welding caused by too short reserved length of the body 221.

Further, referring to fig. 5, in some embodiments, the length L2 of the silver electrode 22 in the first direction may be 1.2mm to 3mm, the length L3 of the body 221 in the first direction may be 0.5mm to 1.5mm, and the protruding height L4 of the overlapping protrusion 222 may be 0.35mm to 0.75mm.

Thus, the overall length L2 of the silver electrode 22 in the first direction, the length L3 of the body 221 and the protruding height L4 of the overlapping protrusion 222 can be reduced as much as possible by reasonably setting the silver paste usage under the condition that the body 221 can be stably welded with the welding strip.

Specifically, in the present invention, the width of the welding strip is usually about 0.35mm, and therefore, the length L3 of the body 221 is set to 0.5mm-1.5mm, which can ensure that it can perform stable welding with the welding strip, in the embodiment of the present invention, the length L3 of the body 221 may be specifically 0.5mm, 0.7mm, 1mm, 1.2mm, 1.5mm, or any value between 0.5mm-1.5mm, which is preferably about 1mm, and is not specifically limited herein. The protrusion height L4 of the overlapping protrusion 222 may be 0.35mm, 0.45mm, 0.55mm, 0.65mm, 0.75mm, or any value between 0.35mm and 0.7mm, which may be preferably 0.55mm.

In addition, it can be understood that, in order to realize that the overlapping convex portion 222 can realize a good overlapping with the first aluminum main grid line 211 and the second aluminum main grid line 212, the width of the silver electrode 22 may be slightly larger than the spacing distance between the first aluminum main grid line 211 and the second aluminum main grid line 212 so that both ends of the silver electrode 22 can be respectively embedded into the first aluminum main grid line 211 and the second aluminum main grid line 212, that is, in the embodiment of the present invention, the spacing distance between the first aluminum main grid line 211 and the second aluminum main grid line 212 is smaller than the length of the silver electrode 22 in the first direction, for example, when the overall length L2 of the silver electrode 22 is 2mm, the length L3 of the body 221 may be set to be about 1mm, the protruding height L4 of the overlapping convex portion 222 may be set to be about 0.5mm, at this time, the spacing distance between the first aluminum main grid line 211 and the second aluminum main grid line 212 may be set to be about 1.6mm, the width of the first aluminum main grid line 211 and the second aluminum main grid line 212 may be set to be about 0.55mm, so that the reliability of the overlapping convex portion and the first aluminum main grid line 211 and the second aluminum main grid line 212 can be ensured.

Example four

Referring to fig. 4, in some embodiments, the plurality of silver electrodes 22 may include a first electrode 223 and a second electrode 224, the first electrode 223 is disposed at an end of each of the first aluminum bus bar 211 and the second aluminum bus bar 212, the plurality of second electrodes 224 are disposed at a middle position of each of the first aluminum bus bar 211 and the second aluminum bus bar 212, and a length of the first electrode 223 is greater than a length of the second electrode 224 in the second direction.

So, to be located the first electrode 223 at first aluminium main grid line 211 and second aluminium main grid line 212 both ends longer can improve the welding performance of the initial solder joint of welding strip and terminal solder joint in order to guarantee welded stability in the second direction, simultaneously, only need set up the first electrode 223 of initial position and terminal position for longer, the second electrode 224 sets up the use of also can effectual reduction silver thick liquid shorter.

Specifically, it can be understood that, in the process of welding the welding strip, the initial welding spot and the terminal welding spot need to keep higher stability to ensure the reliability in the welding process, that is, the welding area of the initial welding spot and the terminal welding spot and the welding strip is relatively large, and therefore, the utility model discloses in, set up the length of first electrode 223 as longer can guarantee the welding strength of the initial welding spot and the terminal welding spot.

As shown in fig. 4, in some embodiments, one first electrode 223 may be disposed at both ends of the first aluminum busbar line 211 and the second aluminum busbar line 212, and a plurality of second electrodes 224 may be disposed between the two first electrodes 223, and during the welding process, the first electrodes 223 at one end may be welded or the first electrodes 223 at both ends may be welded at the same time, and then the second electrode 224 at the middle portion may be welded. Of course, it is understood that in some embodiments, one or more first electrodes 223 may be disposed at the middle position between the first aluminum bus bar 211 and the second aluminum bus bar 212, so that the reliability of the soldering may be further ensured by at least three points with larger soldering area.

In addition, it can be understood that, since the length of the first electrode 223 in the second direction is greater than that of the second electrode 224, in order to ensure the overlapping strength of the first electrode 223 with the first and second aluminum bus bars 211 and 212, the number of the overlapping convex portions 222 on the first electrode 223 may be greater than that of the overlapping convex portions 222 on the second electrode 224, for example, as shown in fig. 4, the number of the overlapping convex portions 222 on the first electrode 223 side may be 3, and the number of the overlapping convex portions 222 on the second electrode 224 side may be 2.

Further, in some embodiments, the length of the first electrode 223 is 2.8mm to 4mm and the length of the second electrode 224 is 1.8mm to 3mm in the second direction.

Thus, through repeated research and verification by the inventors of the present invention, it is found that setting the lengths of the first electrode 223 and the second electrode 224 in the above reasonable range can reduce the usage of silver paste as much as possible while ensuring the welding stability of the first electrode 223 and the second electrode 224 with the welding bar.

Specifically, in such embodiments, the length of the first electrode 223 may be 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, or any value between 2.8mm-4mm, which may preferentially be 2.8mm, and the length of the second electrode 224 may be 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, or any value between 1.8mm-3mm, which may preferentially be 1.8mm.

EXAMPLE five

Referring to fig. 3 and 4, in some embodiments, the sub-gate 23 may include a plurality of first aluminum sub-gate lines 231 and at least one second aluminum sub-gate line 232, the first aluminum sub-gate line 231 is connected to both sides of the main gate 21, and the second aluminum sub-gate line 232 is connected between the first aluminum main gate line 211 and the second aluminum main gate line 212 and located between two adjacent silver electrodes 22.

In this way, the second aluminum sub-gate line 232 can increase the al-si contact in the hollow area between the first aluminum main gate line 211 and the second aluminum main gate line 212 to improve the efficiency of the solar cell 100. That is, the at least one second aluminum sub-grid line 232 disposed between the silver electrodes 22 between the first aluminum main grid line 211 and the second aluminum main grid line 212 can improve the aluminum-silicon contact ratio of the back surface, thereby improving the efficiency of the solar cell 100.

Specifically, in the present embodiment, at least one second aluminum finger line 232 may be disposed between two adjacent silver electrodes 22 between the first aluminum finger line 211 and the second aluminum finger line 212 of each main gate 21, and it is understood that the second aluminum finger line 232 may also be disposed only between part of two adjacent silver electrodes 22, which is not limited herein.

In some embodiments, the heights of the first and second aluminum bus bars 211 and 212 are greater than the height of the silver electrode 22, and the height difference between the first and second aluminum bus bars 211 and 212 and the silver electrode 22 may be 12um to 17um.

Thus, the first aluminum main gate line 211 and the second aluminum main gate line 212 are higher than the silver electrode 22, so that the two ends of the silver electrode 22 can be completely embedded into the first aluminum main gate line 211 and the second aluminum main gate line 212 to improve the contact area and the bonding capability, and meanwhile, the height difference is set in the above range, so that the cost increase caused by too large height difference can be effectively avoided.

Further, as shown in fig. 3 and 4, in some embodiments, each second aluminum finger line 232 may correspond to one first aluminum finger line 231, and the first aluminum finger line 231 corresponding to the second aluminum finger line 232 and the second aluminum finger line 232 are located on the same straight line.

Therefore, when the auxiliary grid 23 is printed and sintered, the first aluminum auxiliary grid line 231 and the second aluminum auxiliary grid line 232 can be directly formed by printing and sintering at one time only by adopting the screen printing plate with a simpler structure, and the manufacturing cost is saved.

Further, in some embodiments, the plurality of first aluminum finger lines 231 may be uniformly spaced along the second direction, the distance between the second aluminum finger line 232 and the silver electrode 22 is N times the distance between two adjacent first aluminum finger lines 231, N is a positive integer and 1 ≦ N ≦ 10.

In this way, the second aluminum finger 232 can be kept at a suitable distance from the silver electrode 22 to avoid the problem of cold joint of the silver electrode 22 during soldering due to the presence of the second aluminum finger 232.

It can be understood that, in such an embodiment, the height of the second aluminum finger line 232231 is usually higher than the height of the silver electrode 22, the distance between the second aluminum finger line 232 and the silver electrode 22 cannot be too small, and when the distance is too small, a cold joint is likely to occur when the solder bar is soldered to the silver electrode 22 due to a certain height difference between the second aluminum finger line 232 and the silver electrode 22. In the present invention, the distance between the adjacent first aluminum busbar lines 231 may be generally set to 0.8mm to 1.2mm, and the distance between the silver electrode 22 and the second aluminum busbar line 232 may be set to 0.8mm to 12mm.

In some embodiments, the distance between the second aluminum finger line 232 and the silver electrode 22 may be 0.8mm-10mm.

Thus, setting the distance between the second aluminum finger line 232 and the silver electrode 22 in the preferred range of 0.8mm-10mm can effectively avoid the occurrence of cold joint caused by the existence of the second aluminum finger line 232 when the solder bar is soldered due to the too close distance between the second aluminum finger line 232 and the silver electrode 22.

Specifically, it is understood that, in the embodiment of the present invention, the main grid 21 and the auxiliary grid 23 may be formed by sequential screen printing and sintering, the height of the main grid 21 and the height of the auxiliary grid 23 are generally higher than the height of the silver electrode 22, and if the distance between the second aluminum auxiliary grid line 232 and the silver electrode 22 is too close, a cold joint is easily caused during welding due to the higher height of the second aluminum auxiliary grid line 232. In the present embodiment, the spacing distance between the second aluminum finger line 232 and the silver electrode 22 may be set to any value between 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, or 0.8mm to 10mm, preferably 3mm to 9mm.

Further, in some embodiments, the solder bars of the solar cell sheet 100 are supported on the second aluminum minor grid lines 232 and are conductively connected to the second aluminum minor grid lines 232.

Like this, when the welding strip, there is certain distance can effectual reduction rosin joint's phenomenon at the interval between second aluminium secondary grid line 232 and the silver-colored electrode 22, and simultaneously, the existence of second aluminium secondary grid line 232 can provide more stable support for the welding strip to avoid the cracked phenomenon of welding strip to appear easily apart from the overlength between two adjacent silver-colored electrodes 22. From another perspective, by the arrangement of the second aluminum busbar line 232, the distance between two adjacent silver electrodes 22 can be further set, so that the number of the silver electrodes 22 of the solar cell 100 is reduced to reduce the use of silver paste, and the cost is saved.

Specifically, in such an embodiment, the height of the second aluminum finger 232 may be higher than or equal to the height of the silver electrode 22, and in order to simplify the manufacturing process, the height of the second aluminum finger 232 may be maintained to be the same as the height of the first aluminum finger 231, both of which are formed by one-time screen printing and sintering.

In the description herein, references to the description of the terms "some embodiments," "exemplary embodiments," "examples," "specific examples," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In addition, the above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalents, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of the present invention.

Claims (10)

1. An electrode structure for a solar cell, comprising:

the main grid comprises a first aluminum main grid line and a second aluminum main grid line which are arranged at intervals along a first direction and extend along a second direction, and the second direction is crossed with the first direction;

the auxiliary grid is connected with the first aluminum main grid line and the second aluminum main grid line; and

the silver electrodes are arranged between the first aluminum main grid line and the second aluminum main grid line, the silver electrodes are arranged at intervals along the second direction, each silver electrode comprises a body and a plurality of overlapping convex parts arranged on two sides of the body in a protruding mode, the body extends along the second direction, the overlapping convex parts extend along the first direction, the overlapping convex parts are arranged at intervals along the second direction with the same sides, the body is arranged at intervals with the first aluminum main grid line and the second aluminum main grid line, and the overlapping convex parts on two sides of the body are respectively in overlapping joint with the first aluminum main grid line and the second aluminum main grid line.

2. The electrode structure according to claim 1, wherein the distance between two adjacent overlapping protrusions located on the same side is 0.4mm to 0.8mm.

3. The electrode structure of claim 1, wherein a ratio of a length of the body to a projection height of the landing tab in the first direction is greater than or equal to 2.

4. The electrode structure according to claim 3, wherein the silver electrode has a length in the first direction of 1.2mm to 3mm, the body has a length in the first direction of 0.5mm to 1.5mm, and the overlap projection has a projection height of 0.35mm to 0.75mm.

5. The electrode structure of claim 1, wherein the plurality of silver electrodes comprises a first electrode and a second electrode, the first electrode is disposed at an end of each of the first and second aluminum bus bars, the second electrode is disposed at a middle position of each of the first and second aluminum bus bars, and a length of the first electrode is greater than a length of the second electrode in the second direction.

6. The electrode structure according to claim 5, wherein the length of the first electrode is 2.8mm to 4mm and the length of the second electrode is 1.8mm to 3mm in the second direction.

7. The electrode structure of claim 1, wherein the secondary grid comprises a plurality of first secondary grid lines and at least one second secondary grid line, the first secondary grid lines are connected to two sides of the primary grid, and the second secondary grid lines are connected between the first aluminum primary grid line and the second aluminum primary grid line and located between two adjacent silver electrodes.

8. A solar cell, comprising:

a substrate;

the electrode structure of any one of claims 1-7, disposed on a back side of the substrate;

and the welding strip is arranged between the first aluminum main grid line and the second aluminum main grid line and is welded with the plurality of silver electrodes.

9. A battery module comprising a plurality of solar cells according to claim 8.

10. A photovoltaic system comprising the cell assembly of claim 9.

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