CN213150791U

CN213150791U - Solar cell and photovoltaic module

Info

Publication number: CN213150791U
Application number: CN202021889597.7U
Authority: CN
Inventors: 徐琛
Original assignee: Longi Green Energy Technology Co Ltd
Current assignee: Longi Green Energy Technology Co Ltd
Priority date: 2020-09-02
Filing date: 2020-09-02
Publication date: 2021-05-07
Anticipated expiration: 2030-09-02

Abstract

The utility model discloses a solar cell and photovoltaic module relates to solar cell technical field to reduce solar cell's series resistance, when improving battery efficiency, simplify solar cell's preparation technology. The solar cell comprises a plurality of sub-cells, an electrode grid line and two external electrodes. The plurality of sub-cells includes first sub-cells and second sub-cells alternately distributed. Each first subcell and each second subcell share the same silicon substrate. The positive terminal of the first sub-battery and the negative terminal of the second sub-battery are located on the first surface of the silicon substrate, and the negative terminal of the first sub-battery and the positive terminal of the second sub-battery are located on the second surface of the silicon substrate. Each first sub-cell is connected with an adjacent second sub-cell in series through a corresponding electrode grid line. Two kinds of external electrodes are formed on two sub-cells at the edges of the plurality of sub-cells. The photovoltaic module comprises the solar cell. The utility model provides a solar cell is arranged in photovoltaic module.

Description

Solar cell and photovoltaic module

Technical Field

The utility model relates to a solar cell technical field especially relates to a solar cell and photovoltaic module.

Background

In the prior art, a crystalline silicon module is formed by connecting single solar cells in series in a welding mode. In the process of manufacturing the component, the component needs to be welded on the main grid through the welding strip, and the welding strip can shield more light, so that the front side of the solar cell is low in current due to shading of the main grid.

At present, half of a solder strip with the length 2 times of the battery side length is generally welded on a front main grid of a solar battery, the other half of the solder strip is welded on a back main grid of a rear adjacent battery piece, and a plurality of battery pieces are connected in series to form a battery string. This technique results in reduced power for the photovoltaic module. In order to improve the power of the solar cell module, the solar cell can be cut into a plurality of completely independent sliced cells by using laser, and then the sliced cells are connected in series according to the series welding mode, so that the current of the cell string is reduced, and the resistance loss of the photovoltaic module is reduced. However, the adoption of the method of cutting the solar cell causes the defect center to be formed on the cutting surface of the solar cell, thereby affecting the efficiency of the solar cell, and the adoption of the method of cutting the solar cell does not reduce the shielding of the main grid on the light receiving surface of the solar cell.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a solar cell and photovoltaic module to reduce solar cell's series resistance, when improving battery efficiency, simplify solar cell's manufacture craft.

In a first aspect, the present invention provides a solar cell. The solar cell includes a plurality of subcells. The plurality of sub-batteries includes: the first sub-battery and the second sub-battery are distributed alternately. Each first subcell and each second subcell share the same silicon substrate. The silicon substrate has opposing first and second sides. The positive terminal of each first subcell and the negative terminal of each second subcell are located on the first face, and the negative terminal of each first subcell and the positive terminal of each second subcell are located on the second face.

The solar cell further comprises an electrode grid line. Each first sub-cell is connected with the adjacent second sub-cell in series through the corresponding electrode grid line. When the electrode grid line is positioned on the first surface, one end of the electrode grid line is formed on the positive electrode end of the first sub-battery, and the other end of the electrode grid line is formed on the negative electrode end of the second sub-battery adjacent to the first sub-battery. When the electrode grid line is positioned on the second surface, one end of the electrode grid line is formed on the positive electrode end of the second sub-battery, and the other end of the electrode grid line is formed on the negative electrode end of the first sub-battery adjacent to the second sub-battery.

The solar cell also comprises two external electrodes. Two kinds of external electrodes are formed on the two sub-cells located at the edges of the plurality of sub-cells.

Adopt under the condition of above-mentioned technical scheme, the utility model provides an among the solar cell, same silicon substrate of each first subcell and each second subcell sharing for each first subcell and each second subcell integration are in same solar cell. The positive terminals of the first sub-batteries and the negative terminals of the second sub-batteries are alternately distributed on the first surface of the silicon substrate, and the negative terminals of the first sub-batteries and the positive terminals of the second sub-batteries are alternately distributed on the second surface of the silicon substrate. At this time, the electrode grid lines can be directly used for connecting different polarity ends of the first sub-cell and the adjacent second sub-cell on the same side, and the first sub-cells and the second sub-cells can be connected in series, so that the interconnection process of the sub-cells in the solar cell is simplified, and the process complexity caused by the fact that welding strips are used for connecting the first sub-cells and the second sub-cells in series is avoided.

Additionally, the utility model provides an among the solar cell, a plurality of subcells are integrated on same silicon substrate for this solar cell need not to utilize electrode grid line concatenation together with a plurality of subcells through the cutting, with reduction shading area and series resistance, improves solar cell power, avoids because the problem that the solar cell efficiency that the cutting battery piece leads to reduces. When the solar cells are interconnected by adopting the solder strips, the placing mode of each sub-cell can be adjusted according to the different number of the sub-cells contained in the cell, so that the external electrodes are positioned on the same side, and the solder strips are positioned on the same side of the two adjacent solar cells when the two adjacent solar cells are interconnected by the solder strips. On the basis, two adjacent solar cells are interconnected by using auxiliary solder strips such as image acquisition equipment and the like, so that the possibility of solder strip deviation is reduced, and the interconnection operability of the solar cells is improved. Meanwhile, the welding strips are located on the same side of the two adjacent solar cells, so that the welding strips do not need to penetrate through gaps between the two adjacent solar cells, the splitting rate of the solar cells and the distance between the solar cells are reduced, and the efficiency of the photovoltaic module is improved.

In a possible implementation manner, a first strip-shaped isolation structure is arranged between the positive terminal of each first sub-battery and the negative terminal of the adjacent second sub-battery, and the width of the first strip-shaped isolation structure between the positive terminal of each first sub-battery and the negative terminal of the adjacent second sub-battery is less than or equal to 500 μm.

Under the condition of adopting the technical scheme, if the first strip-shaped isolation structure exists in the form of the isolation groove, when the electrode grid lines at the positive electrode end of the first sub-battery and the negative electrode end of the second sub-battery can be formed at one time by adopting a screen printing process, a printing process or an electroplating process, the electrode grid lines can be used as the auxiliary grids of the first sub-battery and the second sub-battery, and the positive electrode end of the first sub-battery and the negative electrode end of the second sub-battery can be conveniently connected, so that the process operability is higher. In addition, the width of first strip isolation structure is less than or equal to 500 mu m for distance between first subcell and the adjacent second subcell is smaller, consequently, the utility model provides an among the solar cell, the silicon substrate can be at the integrated more subcells of unit area, makes these subcells pass through the electrode grid line and establishes ties the back, has less series resistance, and then further improves solar cell efficiency.

In one possible implementation manner, when the positive terminal of the first sub-cell and the negative terminal of the second sub-cell are connected through the corresponding electrode grid line, the width of the first strip-shaped isolation structure between the positive terminal of the first sub-cell and the negative terminal of the second sub-cell is less than or equal to 100 μm.

Under the condition of adopting the technical scheme, the screen printing process is adopted to form the electrode grid line at the positive terminal of the first sub-battery and the negative terminal of the second sub-battery, and the formed electrode grid line can be used for reliably connecting the positive terminal of the first sub-battery and the negative terminal of the second sub-battery.

In a possible implementation manner, when the external electrode is located at the positive end of the first sub-battery or the negative end of the second sub-battery, the width of the first strip-shaped isolation structure adjacent to the sub-battery forming the external electrode is 10 μm to 500 μm.

Under the condition of adopting the technical scheme, the positive terminal of the first sub-battery and the negative terminal of the second sub-battery are required to be in a non-contact state so as to prevent short circuit between the sub-battery forming the external electrode and the adjacent sub-battery.

In a possible implementation manner, a second strip-shaped isolation structure is arranged between the negative terminal of each first sub-battery and the positive terminal of the second sub-battery, and the width of the second strip-shaped isolation structure between the negative terminal of each first sub-battery and the positive terminal of each second sub-battery is less than or equal to 500 μm. At this time, the beneficial effects of this technical solution refer to the related description of the first stripe isolation structure.

In a possible implementation manner, when the negative terminal of the first sub-cell is connected with the positive terminal of the adjacent second sub-cell through the corresponding electrode grid line, the width of the second strip-shaped isolation structure between the negative terminal of the first sub-cell and the positive terminal of the adjacent second sub-cell is less than or equal to 100 μm. At this time, the beneficial effects of this technical solution refer to the related description of the first stripe isolation structure.

In a possible implementation manner, when the external electrode is located at the negative end of the first sub-battery or the positive end of the second sub-battery, the width of the second strip-shaped isolation structure adjacent to the sub-battery forming the external electrode is 10 μm to 500 μm.

In one possible implementation manner, the positive terminal of each first sub-cell and the positive terminal of each second sub-cell are both P-type doped layers; and the negative electrode end of each first sub-battery and the negative electrode end of each second sub-battery are both N-type doped layers.

In a possible implementation manner, the first sub-battery and the second sub-battery may be of a heterojunction battery or a common homojunction battery. When the first sub-cell and the second sub-cell are heterojunction cells, a first intrinsic silicon layer is arranged between the P-type doped layer and the silicon substrate; a second intrinsic silicon layer is also disposed between the N-type doped layer and the silicon substrate.

In one possible implementation, each electrode grid line is a screen printed electrode grid line, a printed grid line, or an electroplated grid line. The electrode grid line may be a secondary grid line.

In a possible implementation manner, the total number of the first sub-battery and the second sub-battery is an even number, and the two external electrodes are located on the first surface or the second surface.

In a possible implementation manner, the total number of the first sub-battery and the second sub-battery is an odd number, wherein one external electrode is located on the first surface, and the other external electrode is located on the second surface.

In a second aspect, the present invention provides a photovoltaic module. The photovoltaic cell comprises the solar cell described in the first aspect or any possible implementation manner of the first aspect. And two adjacent solar cells are interconnected through the solder strips.

The beneficial effects of the photovoltaic module provided by the second aspect are the same as those of the solar cell described in the first aspect or any possible implementation manner, and are not described herein again.

Drawings

The accompanying drawings, which are described herein, serve to provide a further understanding of the invention and constitute a part of this specification, and the exemplary embodiments and descriptions thereof are provided for explaining the invention without unduly limiting it. In the drawings:

fig. 1A is a side view of a solar cell according to an embodiment of the present invention;

fig. 1B is a side view of another solar cell provided by an embodiment of the present invention;

fig. 2A is a schematic side view of a solar cell in a same-side external connection state according to an embodiment of the present invention;

fig. 2B is a schematic front view of a solar cell in an external connection state at the same side according to an embodiment of the present invention;

fig. 2C is a schematic back view of a solar cell in a same-side external connection state according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a cell string formed by welding the solar cell strings shown in fig. 2A to 2C;

fig. 4A is a schematic side view of another solar cell in a same-side external connection state according to an embodiment of the present invention;

fig. 4B is a schematic front view of another solar cell in the same-side external connection state according to an embodiment of the present invention;

fig. 4C is a schematic back view of another solar cell in the same-side external connection state according to an embodiment of the present invention;

fig. 5 is a schematic diagram of a cell string formed by welding the solar cell strings shown in fig. 4A to 4C;

fig. 6A is a schematic side view of another solar cell provided by an embodiment of the present invention in an external connection state on an opposite side;

fig. 6B is a schematic front view of another solar cell provided in an embodiment of the present invention in an external connection state on an opposite side;

fig. 6C is a schematic back view of another solar cell provided in an embodiment of the present invention in an external connection state on an opposite side;

fig. 7A is a schematic side view of another solar cell according to an embodiment of the present invention in an external connection state;

fig. 7B is a schematic front view of another solar cell in an external connection state at an opposite side according to an embodiment of the present invention;

fig. 7C is a schematic back view of another solar cell in an external connection state at an opposite side according to an embodiment of the present invention;

fig. 8 is a schematic structural view of a cell string formed by interconnecting the solar cells shown in fig. 6A to 6C;

fig. 9A to 9G are schematic state diagrams of a manufacturing method of a solar cell provided by an embodiment of the present invention at various stages.

Detailed Description

In order to make the technical problem, technical solution and advantageous effects to be solved by the present invention more clearly understood, the following description is given in conjunction with the accompanying drawings and embodiments to illustrate the present invention in further detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

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

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

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", 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 simplification of description, but 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.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

The embodiment of the utility model provides a photovoltaic module can include a plurality of solar cell, and two adjacent solar cell are through welding the area interconnection. And two adjacent solar cells are interconnected through the solder strips. The solder strips are positioned on the same side of the two adjacent solar cells. Based on this, when two adjacent solar cells are interconnected, the two adjacent solar cells are interconnected by using an auxiliary solder strip such as image acquisition equipment, so that the possibility of solder strip deviation is reduced, and the interconnection operability of the solar cells is improved. Meanwhile, the welding strips are located on the same side of the two adjacent solar cells, so that the welding strips do not need to penetrate through gaps between the two adjacent solar cells, the splitting rate of the solar cells and the distance between the solar cells are reduced, and the efficiency of the photovoltaic module is improved.

Fig. 1A and fig. 1B illustrate two schematic structural diagrams of a solar cell provided by an embodiment of the present invention. As shown in fig. 1A and fig. 1B, a solar cell provided by an embodiment of the present invention includes a plurality of sub-cells. The plurality of sub-batteries includes: the first sub-battery and the second sub-battery are distributed alternately. Each first Sub-cell and each second Sub-cell share the same silicon substrate Sub.

As shown in fig. 1A and 1B, the silicon substrate Sub may include, but is not limited to, a single crystal silicon substrate, a polycrystalline silicon substrate, and the like. The silicon substrate Sub has a first face I and a second face II opposed to each other. One of the first surface I and the second surface II faces a light receiving side of the solar cell, and the other faces a backlight side of the solar cell. When the solar cell is a single-sided cell, the first side I may be a light receiving side facing the solar cell, and the second side II may be a backlight side facing the solar cell. Of course, the first surface I may face the backlight side of the solar cell, and the second surface II may face the light receiving side of the solar cell. When the solar cell is a bifacial cell, the first face I and the second face II face in opposite directions.

Each first sub-cell is connected in series with an adjacent second sub-cell via a respective electrode grid line (which may be considered as a sub-grid). The material of the electrode grid line may be one or more of Ag, Al, Cu, W, but is not limited thereto. According to the process of the electrode grid lines, each electrode grid line can be a screen printing electrode grid line, a printing grid line, an electroplating grid line or the like, but is not limited thereto.

As shown in fig. 1A and 1B, the positive terminal CZ1 of each first sub-cell and the negative terminal CF2 of each second sub-cell are located at the first face I, so that the positive terminals CZ1 of the first sub-cells and the negative terminals CF2 of the second sub-cells are alternately distributed at the first face I of the silicon substrate. The negative terminal CF1 of each first subcell and the positive terminal CZ2 of each second subcell are located at the second plane II such that the negative terminal CF1 of the first subcell and the positive terminal CZ2 of the second subcell are alternately distributed at the second plane II of the silicon substrate Sub. In this case, if the electrode grid lines are located on the first plane I, one end of the electrode grid line is formed on the positive terminal CZ1 of the first sub-cell and the other end is formed on the negative terminal CF2 of the second sub-cell adjacent to the first sub-cell, so that each first sub-cell and the adjacent second sub-cell can be connected together in series through the corresponding electrode grid line. If the electrode grid lines are located on the second face II, one end of the electrode grid lines is formed on the positive terminal CZ2 of the second sub-cell and the other end is formed on the negative terminal CF1 of the first sub-cell adjacent to the second sub-cell.

As can be seen from the above, referring to fig. 1A and 1B, the electrode grids can be divided into a first type of electrode grid line AG1 and a second type of electrode grid line AG2 by taking the silicon substrate Sub as a reference, the first type of electrode grid line AG1 is located above the first plane I and connects the positive terminal CZ1 of the first Sub-cell located at the first plane I and the negative terminal CF2 of the adjacent second Sub-cell, and the second type of electrode grid line AG2 is located above the second plane II of the silicon substrate Sub and connects the negative terminal CF1 of the first Sub-cell located at the second plane II and the positive terminal CZ2 of the second Sub-cell. Based on this, when manufacturing the solar cell, after the first Sub-cells and the second Sub-cells are formed on the silicon substrate Sub in an alternating distribution, the first electrode grid lines AG1 may be formed at one time on the surfaces of the positive terminals CZ1 of the respective first Sub-cells and the negative terminals CF2 of the respective second Sub-cells, so that the first electrode grid lines AG1 may be used not only to collect carriers generated by the positive terminals CZ1 of the respective first Sub-cells and carriers generated by the negative terminals CF2 of the respective second Sub-cells, but also to conduct carriers between the positive terminals CZ1 of the first Sub-cells and the negative terminals CF2 of the second Sub-cells. Similarly, the second electrode grid lines AG2 may be formed at one time on the surfaces of the negative terminals CF1 of the respective first sub-cells and the positive terminals CZ2 of the respective second sub-cells, so that the second electrode grid lines AG2 may be used not only for collecting carriers generated by the negative terminals CF1 of the respective first sub-cells and carriers generated by the negative terminals CF2 of the respective second sub-cells, but also for conducting carriers at the negative terminals CF1 of the first sub-cells and the positive terminals CZ2 of the second sub-cells.

Therefore, the embodiment of the utility model provides a solar cell can directly utilize the electrode grid line to connect the different polarity end that has with the first subcell of one side and adjacent second subcell, just can establish ties each first subcell and each second subcell to simplify the interconnection technology of each subcell in the solar cell, avoid adopting to weld the technological complexity that each first subcell of area series connection and each second subcell brought.

In order to extract the current conducted by the electrode grid lines, the solar cell further comprises two external electrodes (which can be regarded as main grids). Two kinds of external electrodes are formed on the two sub-cells located at the edges of the plurality of sub-cells. Because a plurality of sub-batteries are integrated on the same silicon substrate, the solar battery is not required to be cut, and the plurality of sub-batteries are connected in series by utilizing the electrode grid lines, so that the shading area and the series resistance of an external electrode are reduced, the power of the solar battery is improved, and the problem of reduction of the efficiency of the solar battery caused by cutting a battery piece is avoided.

For each external electrode, the external electrode is used as a main gate, and the types of the external electrode include, but are not limited to, a straight-through type, a bamboo joint type, a solder joint type, and the like, and the external electrode may be perpendicular to the electrode gate line, although other non-perpendicular conditions may also exist, which are not listed here. The number of the external electrodes can be at least 1, and the external electrodes can also be multiple. For example: the number of the external electrodes is 1 to 6, and certainly, the number of the external electrodes can also be 2 to 4. Under the condition, the number of the external electrodes formed by the sub-battery pieces is controlled, unnecessary shading is reduced, and the light utilization rate is improved. The width of each external electrode can be 0.1 mm-1 mm, and also can be 0.2 mm-0.6 mm, so as to ensure that the external electrodes can be reliably formed on the sub-battery, reduce unnecessary shading and improve the light utilization rate. If one end (which may be a positive end or a negative end) of a certain sub-cell has an external electrode, the number of the fine grids at the end of the sub-cell may be 40 to 120, or 60 to 100. The width of the fine gate is 20-120 μm, or 30-60 μm.

When the first sub-battery and the second sub-battery are alternately distributed, the sub-battery where the two external electrodes are located is the first sub-battery or the second sub-battery, and the total number of the first sub-battery and the second sub-battery is related. As shown in fig. 1A and 1B, when the external connection electrode is formed at the positive terminal CZ1 of the first subcell, the positive terminal CZ1 of the first subcell is not connected to the negative terminal CF2 of the adjacent second subcell through the electrode grid line, so as to avoid short circuit of the solar cell formed by a plurality of subcells. Similarly, when the external electrode is formed at the negative terminal CF1 of the first sub-cell, the negative terminal CF1 of the first sub-cell is not connected to the positive terminal CZ2 of the adjacent second sub-cell through the electrode grid line; when the external electrode is formed at the positive terminal CZ2 of the second sub-cell, the positive terminal CZ2 of the second sub-cell is not connected with the negative terminal CF1 of the adjacent first sub-cell through the electrode grid line; when the external connection electrode is formed at the negative terminal CF2 of the second sub-cell, the negative terminal CF2 of the second sub-cell is not connected to the positive terminal CZ1 of the adjacent first sub-cell through the electrode grid line.

The total number of the first sub-battery and the second sub-battery may be 2 to 6, and may be 2 to 4. As described in detail below. For convenience of description, the two kinds of external electrodes may be defined as a first kind of external electrode MG1 and a second kind of external electrode MG2 as shown in fig. 1A and 1B.

As shown in fig. 1A, when the total number of the first Sub-batteries and the second Sub-batteries is an even number, the first external connection electrode MG1 and the second external connection electrode MG2 are located above the same surface of the silicon substrate Sub. For example: the first external electrode MG1 and the second external electrode MG2 are located on the first face I. Another example is: the first external electrode MG1 and the second external electrode MG2 are located on the second face II.

As shown in fig. 1A, when the first face I is a backlight side of the solar cell, the first external electrode MG1 and the second external electrode MG2 are located on the first face I. When the first side I is the light-facing side of the solar cell, the first external connection electrode MG1 and the second external connection electrode MG2 are located above the second side II. It follows that when the total number of the first and second sub-cells is an even number, the first and second sub-cells may be formed on the same side of the solar cell.

Fig. 2A to fig. 2C illustrate schematic diagrams of a solar cell provided by an embodiment of the present invention at different viewing angles. Wherein, fig. 2A is the embodiment of the utility model provides a solar cell is at the schematic diagram that looks sideways at of the external state of homonymy, fig. 2B is the embodiment of the utility model provides a positive schematic diagram of a solar cell at the external state of homonymy, fig. 2C is the embodiment of the utility model provides a back schematic diagram of a solar cell at the external state of homonymy.

As shown in fig. 2A to fig. 2C, a solar cell provided by an embodiment of the present invention includes 1 first Sub cell and 1 second Sub cell integrated on the same silicon substrate Sub. The first surface I may be a light-receiving surface of the solar cell, and the second surface II may be a backlight surface of the solar cell.

As shown in fig. 2A to 2C, the positive terminal CZ1 of the first sub-cell and the negative terminal CF2 of the second sub-cell are located on fig. 2A, and the negative terminal CF1 of the first sub-cell and the positive terminal CF1 of the second sub-cell are located below fig. 2A. The positive electrode terminal CZ1 of the first sub-battery and the negative electrode terminal CF2 of the second sub-battery are connected through a first electrode grid line AG1, and 1 first external electrode MG1 is formed at the negative electrode terminal CF1 of the first sub-battery and is used for leading out electrons; the positive terminal CZ2 of the second sub-cell is formed with 1 second external electrode MG2 for leading out holes.

Fig. 3 is a schematic view illustrating a cell string to which the solar cell string shown in fig. 2A to 2C is soldered. As shown in fig. 3, when m solar cells are used to form a Cell string, the adjacent two solar cells may be rotated by 180 °, so that the adjacent two cells are placed in opposite directions, and the first external electrode MG1 of one solar Cell is located on the same side as the second external electrode MG2 of the adjacent solar Cell. And the negative terminal CF1 of the first sub-Cell and the positive terminal CZ2 of the second sub-Cell included in each solar Cell are located on the back surface of the solar Cell.

Two adjacent solar cells in series are connected in series on the back of the solar cells by using 1 welding strip HD. On the basis, 1 welding strip is welded or bonded on the negative end CF1 of the first sub-cell contained by the first solar cell and the positive end CZ2 of the second sub-cell contained by the second solar cell, so that the 1 welding strip welded or bonded on the negative end CF1 of the first sub-cell is the positive electrode welding strip HZ, and the welding strip welded or bonded on the positive end CZ2 of the second sub-cell is the negative electrode welding strip HF. As can be seen from fig. 3, the positive electrode bonding tape HZ and the negative electrode bonding tape HF are located at both ends of the battery string.

Taking a cell string formed by interconnecting 3 solar cells as an example, the cell string comprises 3 rectangular solar cells with the same size, namely a first solar cell, a second solar cell and a third solar cell. As shown in fig. 3, the positive terminal CZ2 of the second subcell included in the first solar cell, the negative terminal CF1 of the first subcell included in the second solar cell, and the positive terminal CZ2 of the second subcell included in the third solar cell are all located above in fig. 3. The negative terminal CF1 of the first sub-cell included in the first solar cell, the positive terminal CZ of the second sub-cell included in the second solar cell, and the negative terminal CF1 of the first sub-cell included in the third solar cell are all located below fig. 3, and on the basis thereof, 1 solder ribbon is welded or bonded to the first external electrode MG1 formed on the negative terminal CF1 of the first sub-cell included in the first solar cell and the second external electrode MG2 formed on the positive terminal CZ2 of the second sub-cell included in the second solar cell, and 1 solder ribbon is welded or bonded to the first external electrode MG1 formed on the negative terminal CF1 of the first sub-cell included in the second solar cell and the second external electrode MG2 formed on the positive terminal CZ2 of the second sub-cell included in the third solar cell. As shown in fig. 2A to 2C and 3, 1 solder tape is welded or bonded to the first external connection electrode MG1 formed at the negative terminal CF1 of the first sub-cell included in the third solar cell, and 1 solder tape is welded or bonded as the negative electrode solder tape HF to the second external connection electrode MG2 formed at the positive terminal CZ2 of the second sub-cell included in the first solar cell, and as the positive electrode solder tape HZ.

Fig. 4A to 4C are schematic diagrams illustrating another solar cell provided by an embodiment of the present invention at different viewing angles. Wherein, fig. 4A is the utility model provides another kind of solar cell looks sideways at the schematic diagram of looking sideways at the external state of homonymy, fig. 4B is the utility model provides a positive schematic diagram of another kind of solar cell at the external state of homonymy, fig. 4C is the utility model provides a another kind of solar cell is at the back schematic diagram of the external state of homonymy.

As shown in fig. 4A to 4C, the solar cell provided by the embodiment of the present invention includes 2 first Sub cells and 2 second Sub cells integrated on the same silicon substrate Sub. Defining 2 first sub-batteries as 1# sub-battery and 3# sub-battery, and 2 second sub-batteries as 2# sub-battery and 4# sub-battery. For the silicon substrate Sub, the first surface I may be a light receiving surface of the solar cell, and the second surface II may be a backlight surface of the solar cell.

As shown in fig. 4A to 4C, the positive terminal CZ1 of the 1# sub-cell, the negative terminal CF2 of the 2# sub-cell, the positive terminal CZ3 of the 3# sub-cell and the negative terminal CZ4 of the 4# sub-cell are distributed on the first plane I. At this time, the positive terminal CZ1 of the 1# sub-cell and the negative terminal CF2 of the 2# sub-cell are connected by the first type of electrode grid line AG1, and the positive terminal CZ3 of the 3# sub-cell and the negative terminal CZ4 of the 4# sub-cell are connected by the first type of electrode grid line AG 1.

As shown in fig. 4A to 4C, the negative terminal CF1 of the 1# sub-cell, the positive terminal CZ2 of the 2# sub-cell, the negative terminal CF3 of the 3# sub-cell, and the positive terminal CZ4 of the 4# sub-cell are distributed on the second plane II. At this time, the positive terminal CZ2 of the 2# sub-cell and the negative terminal CF3 of the 3# sub-cell are connected by the second electrode grid line AG 2. Meanwhile, the negative terminal CF1 of the 1# sub-battery is formed with 2 first external electrodes MG1 for leading out electrons. The positive terminal CZ4 of the 4# sub-battery is formed with 2 second external electrodes MG2 for leading out holes.

Fig. 5 is a schematic view illustrating a cell string to which the solar cell string shown in fig. 4A to 4C is soldered. As shown in fig. 5, when m solar cells are used to form a Cell string, two adjacent solar cells may be rotated 180 °, so that the two adjacent cells are placed in opposite directions. At this time, the negative terminal CF1 of the 1# sub-Cell and the positive terminal CZ4 of the 4# sub-Cell included in each solar Cell are located on the rear surface of the solar Cell. And 2 welding strips are used for connecting two adjacent solar cells in series on the back surfaces of the solar cells, so that a Cell string positive electrode welding strip HZ and a Cell string negative electrode welding strip HF of the Cell string are positioned at two ends of the Cell string.

Taking a cell string formed by interconnecting 3 solar cells as an example, the cell string comprises 3 rectangular solar cells with the same size, namely a first solar cell, a second solar cell and a third solar cell. As shown in fig. 5, the positive terminal CZ4 of the 4# subcell included in the first solar cell, the negative terminal CF1 of the 1# subcell included in the second solar cell, and the positive terminal CZ4 of the 4# subcell included in the third solar cell are all located above fig. 5. The negative terminal CF1 of the 1# subcell included in the first solar cell, the positive terminal CZ4 of the 4# subcell included in the second solar cell, and the negative terminal CF1 of the 1# subcell included in the third solar cell are all located below in fig. 5. On the basis of this, 2 solder tapes are welded or bonded to the first external connection electrode MG1 formed on the negative terminal CF1 of the 1# sub-cell included in the first solar cell and to the second external connection electrode MG2 formed on the positive terminal CZ4 of the 4# sub-cell included in the second solar cell, and 2 solder tapes are welded or bonded to the first external connection electrode MG1 formed on the negative terminal CF1 of the 1# sub-cell included in the second solar cell and to the second external connection electrode MG2 formed on the positive terminal CZ4 of the 4# sub-cell included in the third solar cell. Meanwhile, as shown in fig. 4A to 4C and 5, 2 solder tapes were welded or bonded as positive electrode solder tapes HZ to the second external connection electrode MG2 formed at the positive electrode terminal CZ4 of the 4# sub-cell included in the first solar cell. 2 solder tapes are soldered or bonded as negative electrode solder tapes HF on the first external connection electrode MG1 formed at the negative terminal CF1 of the 1# sub-cell included in the fourth solar cell.

As can be seen from the above, as shown in fig. 4A to 4C and fig. 5, when the total number of the first sub-battery and the second sub-battery of the first external electrode MG1 and the second external electrode MG2 is even, the types of the sub-batteries where the first external electrode MG1 and the second external electrode MG2 are located are the first sub-battery and the second sub-battery, respectively. And the first external electrode MG1 and the second external electrode MG2 are located on the same side of the solar cell, so that when the solar cells are interconnected, one of the two adjacent solar cells can be rotated by 180 ℃, and the two adjacent solar cells are interconnected by solder strips distributed along the string extending direction of the battery string on the backlight surfaces of the two adjacent solar cells. Therefore, the embodiment of the utility model provides a solar cell is when the interconnection, and the welding strip need not to extend to the back after solar cell's front is buckled, realizes two adjacent solar cell interconnections, consequently, the utility model provides a during solar cell interconnection, when adopting welding or bonding process to form the welding strip on the external electrode, need not to consider welding process or bonding process to the produced adverse effect of the positive terminal of first subcell and the negative pole section of second subcell, can adopt real-time detection such as image sensor to weld the strip and whether have the piece skew problem, reduced the probability and the lobe of a leaf rate of welding strip skew to reduce and weld the strip and form the technology degree of difficulty, reduced the interval between the silicon chip simultaneously, thereby promote solar module's efficiency.

As shown in fig. 1B, when the total number of the first sub-battery and the second sub-battery is an odd number, one of the external electrodes is located on the first surface I, and the other external electrode is located on the second surface II. In this case, one of the external electrodes may be a light receiving side of the solar cell, and the other external electrode may be a backlight side of the solar cell. At the moment, the shading area of the external electrode to the solar cell can be reduced, and the light utilization rate is improved.

Fig. 6A to 6C are schematic diagrams illustrating another solar cell provided by an embodiment of the present invention at different viewing angles. Wherein, fig. 6A is the embodiment of the utility model provides a schematic diagram that looks sideways at of another solar cell in the external state of heteropleural, fig. 6B is the embodiment of the utility model provides a front schematic diagram of another solar cell in the external state of heteropleural, fig. 6C is the embodiment of the utility model provides a back schematic diagram of another solar cell in the external state of heteropleural.

As shown in fig. 6A to 6C, the solar cell provided by the embodiment of the present invention includes 2 first Sub cells and 1 second Sub cell integrated on the same silicon substrate Sub. Defining 1 first sub-battery as 1# sub-battery and 3# sub-battery, and 1 second sub-battery as 2# sub-battery. For the silicon substrate Sub, the first surface I may be a light receiving surface of the solar cell, and the second surface II may be a backlight surface of the solar cell.

As shown in fig. 6A to 6C, the positive terminal CZ1 of the 1# sub-cell, the negative terminal CF2 of the 2# sub-cell, and the positive terminal CZ3 of the 3# sub-cell are distributed on the first plane I. At this time, the positive terminal CZ1 of the 1# sub-cell and the negative terminal CF2 of the 2# sub-cell are connected by the first electrode grid line AG 1. The negative terminal CF1 of the # 1 subcell, the positive terminal CZ2 of the # 2 subcell, and the negative terminal CF3 of the # 3 subcell are distributed on the second face II. At this time, the positive terminal CZ2 of the 2# sub-cell and the negative terminal CF3 of the 3# sub-cell are connected by the second electrode grid line AG 2. The negative terminal CF1 of the 1# sub-battery is formed with a first external electrode MG1 for deriving electrons. The positive terminal CZ3 of the 3# sub-battery is formed with a second external electrode MG2 for leading out holes.

Fig. 7A to 7C are schematic diagrams illustrating another solar cell provided by an embodiment of the present invention at different viewing angles. Wherein, fig. 7A is the embodiment of the utility model provides a schematic diagram that looks sideways at of another solar cell in the external state of heteropleural, fig. 7B is the utility model provides a positive schematic diagram of another solar cell in the external state of heteropleural, fig. 7C is the utility model provides a back schematic diagram of another solar cell in the external state of heteropleural.

As shown in fig. 7A to 7C, the solar cell provided by the embodiment of the present invention includes 1 first Sub cell and 2 second Sub cells integrated on the same silicon substrate Sub. 2 second sub-batteries are defined as a 1# sub-battery and a 3# sub-battery, and 1 first sub-battery is defined as a 2# sub-battery. For the silicon substrate Sub, the first surface I may be a light receiving surface of the solar cell, and the second surface II may be a backlight surface of the solar cell.

As shown in fig. 7A to 7C, the negative terminal CF1 of the 1# sub-cell, the positive terminal CZ2 of the 2# sub-cell, and the negative terminal CF3 of the 3# sub-cell are distributed on the first face I. At this time, the negative terminal CF1 of the 1# sub-cell and the positive terminal CZ2 of the 2# sub-cell are connected by the first electrode grid line AG 1. The positive terminal CZ1 of the 1# sub-cell, the negative terminal CF2 of the 2# sub-cell and the positive terminal CZ3 of the 3# sub-cell are distributed on the second face II. At this time, the negative terminal CF2 of the 2# subcell and the positive terminal CZ3 of the 3# subcell are connected by a second electrode grid line AG 2. The positive terminal CZ1 of the 1# sub-battery is formed with a first external electrode MG1 for leading out holes. The negative terminal CF3 of the 3# sub-battery is formed with a second external electrode MG2 for deriving electrons.

Fig. 8 is a schematic view illustrating a structure of a cell string in which the solar cells shown in fig. 6A to 6C are interconnected. As shown in fig. 8, the Cell string includes m solar cells Cell. Each solar cell is a bifacial solar cell. By adjusting the placing mode of the two adjacent solar cells, the solder strips interconnecting the two adjacent solar cells are positioned on the same side in the formed photovoltaic module. The following description will be made by taking as an example a cell string in which solar cells shown in fig. 6A to 6C are interconnected. The interconnected cell string of solar cells shown in fig. 7A to 7C can be referred to below.

As shown in fig. 8, the cell string includes 3 rectangular solar cells of the same size, namely a first solar cell, a second solar cell and a third solar cell. And adjusting the positive and negative directions of the three solar cells to ensure that the light facing surface of the second solar cell, the light facing surface of the first solar cell and the light facing surface of the third solar cell are positioned at one side, and the light facing surface of the second solar cell, the light facing surface of the first solar cell and the light facing surface of the third solar cell are positioned at the other side. At this time, the negative terminal CF1 of the 1# sub cell included in the first solar cell, the positive terminal CZ3 of the 3# sub cell included in the second solar cell, and the negative terminal CF1 of the 1# sub cell included in the third solar cell are all located above fig. 8, and the positive terminal CZ3 of the 3# sub cell included in the first solar cell, the negative terminal CF1 of the 1# sub cell included in the second solar cell, and the positive terminal CZ3 of the 3# sub cell included in the third solar cell are all located below fig. 8. On this basis, 2 solder strips are welded or bonded to the first external connection electrode MG1 formed at the negative terminal CF1 of the 1# sub-cell included in the first solar cell and the second external connection electrode MG2 formed at the positive terminal CZ3 of the 3# sub-cell included in the second solar cell, and 2 solder strips are welded or bonded to the second external connection electrode MG2 formed at the negative terminal CF3 of the 3# sub-cell included in the second solar cell and the first external connection electrode MG1 formed at the positive terminal CZ1 of the 1# sub-cell included in the third solar cell. Meanwhile, 2 positive electrode ribbons HZ are welded or adhered to the second external electrode MG2 formed at the positive terminal CZ3 of the 3# sub-cell included in the first solar cell. The first external electrode MG1 formed at the negative terminal CF1 of the 1# sub-cell included in the third solar cell was welded or adhered with 2 negative electrode welding strips HF. In fig. 8, the broken lines are shown on the back side of the paper, and for convenience of illustration, the solder ribbons on the front side and the back side of the paper are shown in the same drawing.

As can be seen from the above description, when the total number of the first sub-battery and the second sub-battery is odd, the types of the sub-batteries where the first external electrode MG1 and the second external electrode MG2 are located are the same. And whether the sub-battery is the first sub-battery or the second sub-battery is related to the sequence of the first sub-battery and the second sub-battery which are alternately distributed on the silicon chip. Moreover, because the first external electrode MG1 and the second external electrode MG2 are located on different sides of the solar cell, when the solar cells are interconnected, the front and back orientations of two adjacent solar cells need to be adjusted, so that when the two adjacent solar cells are interconnected, the different polarity ends of the two adjacent solar cells can be welded or bonded together through the solder strip on the same side. Therefore, the embodiment of the utility model provides a solar cell is when the interconnection, and the welding strip need not to extend to the back after solar cell's front is buckled, realizes two adjacent solar cell interconnections, consequently, the utility model provides a during solar cell interconnection, when adopting welding or bonding process to form the welding strip on the external electrode, need not to consider welding process or bonding process to the produced adverse effect of the positive terminal of first subcell and the negative pole section of second subcell, can adopt real-time detection such as image sensor to weld the strip and whether have the piece skew problem, reduced the probability and the lobe of a leaf rate of welding strip skew to reduce and weld the strip and form the technology degree of difficulty, reduced the interval between the silicon chip simultaneously, thereby promote solar module's efficiency.

In an alternative, as shown in fig. 1A to 2A, a first strip-shaped isolation structure FG1 is provided between the positive terminal CZ1 of each first sub-cell and the negative terminal CF2 of the adjacent second sub-cell. The width of the first stripe-like isolation structure FG1 between the two is less than or equal to 500 μm. When the width of the first strip-like isolation structure FG1 between the two is equal to 0 μm, the first strip-like isolation structure FG1 may be regarded as a virtual structure located between the positive terminal CZ1 of each first subcell and the negative terminal CF2 of the adjacent second subcell. At this time, the positive terminal CZ1 of each first sub-cell is substantially in contact with the negative terminal CF2 of the adjacent second sub-cell. When the width of the first strip-like isolation structure FG1 between the two is greater than 0 μm and less than or equal to 500 μm, the first strip-like isolation structure FG1 is located as a solid structure between the positive terminal CZ1 of each first subcell and the negative terminal CF2 of the adjacent second subcell.

As shown in fig. 1A and 1B, when the positive terminal CZ1 of the first sub-cell and the negative terminal CF2 of the second sub-cell are connected by respective electrode grid lines, the width of the first stripe-shaped isolation structure FG1 therebetween is less than or equal to 100 μm. That is, the positive terminal CZ1 of the first sub-cell may be in contact with the negative terminal CF2 of the second sub-cell, and may also have the first stripe-shaped isolation structure FG1 as a solid structure, except that the width of the first stripe-shaped isolation structure FG1 is not more than 100 μm.

In the application scenario shown in fig. 2A to 2C, fig. 4A to 4B, fig. 6A to 6C, and fig. 7A to 7C, when the positive terminal CZ1 of the first sub-cell and the negative terminal CF2 of the second sub-cell have a first stripe-shaped isolation structure FG1 (with a width greater than 0 μm and less than or equal to 500 μm, or 100 μm, or 10 μm and 50 μm) therebetween, the first electrode grid line AG1 can be used as a carrier conduction carrier to conduct carriers between the positive terminal CZ1 of the first sub-cell and the negative terminal CF2 of the second sub-cell. Even if the positive terminal CZ1 of the first sub-cell and the negative terminal CF2 of the second sub-cell are in contact, more paths are provided for the conduction of carriers of the positive terminal CZ1 of the first sub-cell and the negative terminal CF2 of the second sub-cell, and the series connection of the first sub-cell and the second sub-cell is not affected.

As shown in fig. 6A to 6C and 7A to 7C, when the external connection electrode is located at the positive terminal of the first sub-cell or the negative terminal of the second sub-cell, the width of the first stripe-shaped isolation structure adjacent to the sub-cell forming the external connection electrode is 10 μm to 500 μm. That is, the width of the first stripe-shaped isolation structure adjacent to the sub-cell forming the external connection electrode needs to be greater than 0. At this time, the first stripe isolation structure FG1 may reduce the probability of short circuit occurring when the sub-cell where the external electrode is located is electrically contacted with an adjacent sub-cell. When the width of the first strip-shaped isolation structure is 80-200 μm, the short circuit probability of the sub-battery where the external electrode is located and the adjacent sub-battery in electrical contact can be further reduced under the condition that the number of the battery pieces connected in series is ensured as much as possible.

In the application scenario shown in fig. 6A to 6C, if the negative terminal CF2 of the 2# sub-cell is connected to the positive terminal CZ3 of the 3# sub-cell, the solar cell formed by the 1# sub-cell, the 2# sub-cell and the 3# sub-cell is short-circuited, and the solar cell cannot operate normally. If the first strip-shaped isolation structure FG1 (with the width greater than 0 μm and less than or equal to 500 μm or 10 μm to 500 μm) is arranged between the negative end CF2 of the 2# sub-cell and the positive end CZ3 of the 3# sub-cell, the solar cell formed by the 1# sub-cell, the 2# sub-cell and the 3# sub-cell can not be short-circuited and can normally lead out current.

Similarly, in the application scenario shown in fig. 7A to 7C, a first stripe isolation structure FG1 (with a width greater than 0 μm and less than or equal to 500 μm, or 10 μm to 500 μm) is provided between the positive terminal CZ2 of the # 2 subcell and the negative terminal CF3 of the # 3 subcell, so that the solar cell formed by the # 1 subcell, the # 2 subcell and the # 3 subcell will not be short-circuited and can normally draw out current.

In one example, as shown in fig. 1A and 1B, the first stripe isolation structure FG1 may be an insulating isolation stripe made of an insulating material such as silicon oxide or aluminum oxide, or may be an isolation trench. The isolation trench can be formed by common methods such as masking, chemical etching, plasma etching and the like.

As shown in fig. 1A and 1B, when the first stripe-shaped isolation structure FG1 is an insulating isolation bar, the insulating isolation bar may serve as a support structure to support an electrode grid line between the positive terminal CZ1 of a first sub-cell and the negative terminal CF2 of an adjacent second sub-cell, and thus, various processes may be employed to normally form a first electrode grid line AG1 at the surface of the positive terminal CZ1 of each first sub-cell and the negative terminal CF2 of each second sub-cell. These processes include, but are not limited to, deposition processes, 3D printing processes, inkjet printing processes, screen printing processes, metal plating processes (e.g., copper plating processes, silver plating processes, etc.).

As shown in fig. 1A and 1B, when the first strip-shaped isolation structure FG1 is an isolation groove, there is a gap between the positive terminal CZ1 of the first sub-cell and the negative terminal CF2 of the adjacent second sub-cell. At this time, when the first electrode grid lines AG1 are normally formed on the surfaces of the positive terminals CZ1 of the first sub-cells and the negative terminals CF2 of the second sub-cells by a deposition process such as a sputtering process, the portions of the first electrode grid lines AG1 above the isolation grooves may be broken, and the solar cell may not be able to conduct current. In order to solve the problem, the width of the first stripe isolation structure FG1 and the width of the electrode gate line may be improved from two angles, so as to reduce the possibility of the electrode gate line breaking at the position above the isolation trench.

As shown in fig. 1A and 1B, the width of the first stripe-shaped isolation structure FG1 therebetween is less than 500 μm in terms of the width of the first stripe-shaped isolation structure FG 1. At this time, the width of the first stripe isolation structure FG1 is relatively small. When the first stripe-shaped isolation structure FG1 is an isolation groove, a screen printing process, a printing process, or an electroplating process may be used to form the first kind of electrode grid line AG1 at one time at the positive terminal CZ1 of the first sub-cell and the negative terminal CF2 of the second sub-cell.

As shown in fig. 1A and 1B, when the positive terminal CZ1 of the first sub-battery is connected to the negative terminal CF2 of the second sub-battery through the corresponding first electrode grid line AG1, and the width of the first stripe-shaped isolation structure FG1 therebetween is less than or equal to 100 μm, the distance between the positive terminal CZ1 of the first sub-battery and the negative terminal CF2 of the second sub-battery is relatively small, so that when the first stripe-shaped isolation structure FG1 is an isolation groove and an electrode grid line is formed by a screen printing process, a printing process or an electroplating process, the first electrode grid line AG1 is relatively less likely to be broken at a portion above the isolation groove, thereby improving the connection reliability of the first electrode grid line AG 1.

As shown in fig. 1A and 1B, the width of the first electrode grid AG1 ranges from 20 μm to 200 μm, but may also range from 40 μm to 100 μm, in terms of the width of the first electrode grid AG 1. At this time, the width of the first electrode grid line AG1 not only can meet the requirement of current conduction, but also has a certain strength, so when the first strip-shaped isolation structure FG1 is an isolation groove, the first electrode grid line AG1 formed by a screen printing process, a printing process, or an electroplating process is not easily broken above the isolation groove, thereby improving the connection reliability of the first electrode grid line AG 1. Meanwhile, when the negative terminal CF1 of the first sub-battery is connected with the positive terminal CZ2 of the second sub-battery through the first electrode grid lines AG1, the number of the first electrode grid lines AG1 may range from 50 to 150, and may also range from 80 to 120. When the first strip-shaped isolation structures FG1 are isolation grooves, the first strip-shaped isolation structures FG1 crossing over the isolation grooves are multiple, so that one of the first strip-shaped isolation structures FG1 is broken due to insufficient supporting force of the isolation grooves, and there may be other first strip-shaped isolation structures FG1 to realize the series connection of the first subcell and the adjacent second subcell. Meanwhile, in the range, the number of the first strip-shaped isolation structures FG1 is small, so that unnecessary shading can be reduced, and the light utilization rate is improved.

In an alternative, as shown in fig. 1A and 1B, a second strip-shaped isolation structure FG2 is provided between the negative terminal CZ1 of each of the first sub-cells and the positive terminal CZ2 of the second sub-cell. The width of the second stripe-like isolation structure FG2 between the two is less than or equal to 500 μm. When the width of the second stripe-shaped isolation structure FG2 between the two is equal to 0 μm, the second stripe-shaped isolation structure FG2 between the two may be regarded as a virtual structure located between the negative terminal CF1 of each first sub-cell and the positive terminal CZ2 of the adjacent second sub-cell. At this time, the negative terminal CF1 of each first sub-cell is substantially in contact with the positive terminal CZ2 of the adjacent second sub-cell. When the width of the second stripe-shaped isolation structure FG2 between the two is greater than 0 μm and less than or equal to 500 μm, the second stripe-shaped isolation structure FG2 is located between the negative terminal CF2 of each second subcell and the positive terminal CZ2 of the adjacent second subcell as a solid structure.

As shown in fig. 1A and 1B, when the negative terminal CF1 of a first sub-cell is connected to the positive terminal CZ2 of an adjacent second sub-cell by a corresponding electrode grid line, the width of the second striped isolation structure FG2 is less than or equal to 100 μm. That is, the negative terminal CF1 of the first sub-cell may be in contact with the positive terminal CZ2 of the adjacent second sub-cell, and may also have the second stripe-shaped isolation structure FG2 as a solid structure, except that the width of the second stripe-shaped isolation structure FG2 therebetween is less than or equal to 100 μm.

In the application scenario shown in fig. 4A to 4C, when there is a second stripe-shaped isolation structure FG2 (with a width greater than 0 μm and less than or equal to 500 μm, or 100 μm, or 10 μm to 50 μm) between the positive terminal CZ2 of the 2# sub-cell and the negative terminal CF3 of the 3# sub-cell), the second electrode grid line AG2 may serve as a carrier conduction carrier to conduct carriers between the positive terminal CZ2 of the 2# sub-cell and the negative terminal CF3 of the 3# sub-cell. Even if the positive terminal CZ2 of the 2# sub-cell is in contact with the negative terminal CF3 of the 3# sub-cell, more paths are provided for the conduction of carriers of the positive terminal CZ2 of the 2# sub-cell and the negative terminal CF3 of the 3# sub-cell, and the series effect of the 2# sub-cell and the 3# sub-cell is not influenced.

As shown in fig. 2A to 2C and 4A to 4C, when the external connection electrode is located at the negative terminal CF1 of the first sub-cell or the positive terminal CZ2 of the second sub-cell, the width of the second stripe-shaped isolation structure FG2 adjacent to the sub-cell forming the external connection electrode is 10 μm to 500 μm. That is, the width of the second stripe-shaped isolation structure FG2 adjacent to the sub-cell forming the external connection electrode needs to be greater than 0. At this time, the second stripe-shaped isolation structure FG2 can reduce the probability of short circuit occurring when the sub-cell where the external electrode is located is electrically contacted with the adjacent sub-cell. When the width of the second strip-shaped isolation structure FG2 is 80-200 μm, the short circuit probability of the sub-battery where the external electrode is located and the adjacent sub-battery in electric contact can be further reduced under the condition that the serial number of the battery pieces is ensured as much as possible.

In the application scenario shown in fig. 4A to 4C, if the negative terminal CF1 of the 1# sub-cell is connected to the positive terminal CZ2 of the 2# sub-cell, the solar cell formed by the 1# sub-cell, the 2# sub-cell, the 3# sub-cell and the 4# sub-cell is short-circuited, and the solar cell cannot normally operate. If the second strip-shaped isolation structure FG2 (with the width greater than 0 μm and less than or equal to 500 μm or 10 μm to 500 μm) is arranged between the negative end CF1 of the 1# sub-cell and the positive end CZ2 of the 2# sub-cell, the solar cell formed by the 1# sub-cell, the 2# sub-cell, the 3# sub-cell and the 4# sub-cell can not be short-circuited and can normally lead out current.

Similarly, in the application scenario shown in fig. 4A to 4C, the second stripe-shaped isolation structure FG2 (with a width greater than 0 μm and less than or equal to 500 μm, or 10 μm to 500 μm) is provided between the negative terminal CF3 of the # 3 subcell and the positive terminal CZ4 of the # 4 subcell, so that the solar cell formed by the # 1 subcell, the # 2 subcell, the # 3 subcell and the # 4 subcell will not be short-circuited and can normally derive the current.

Similarly, in the application scenario shown in fig. 6A to 6C, if the second stripe-shaped isolation structure FG2 (having a width greater than 0 μm and less than or equal to 500 μm, or 10 μm to 500 μm) is provided between the negative terminal CF1 of the 1# sub-cell and the positive terminal CZ2 of the 2# sub-cell, the solar cell formed by the 1# sub-cell, the 2# sub-cell and the 3# sub-cell will not be short-circuited, and the current can be normally derived.

Similarly, in the application scenario shown in fig. 7A to 7C, if the second stripe-shaped isolation structure FG2 (having a width greater than 0 μm and less than or equal to 500 μm, or 10 μm to 500 μm) is provided between the positive terminal CZ1 of the 1# sub-cell and the negative terminal CF1 of the 2# sub-cell, the solar cell formed by the 1# sub-cell, the 2# sub-cell and the 3# sub-cell will not be short-circuited, and the current can be normally derived.

In one example, as shown in fig. 1A and 1B, the second stripe-shaped isolation structure FG2 may be an insulating isolation stripe made of an insulating material such as silicon oxide or aluminum oxide, or may be an isolation trench. The isolation trench can be formed by common methods such as masking, chemical etching, plasma etching and the like.

As shown in fig. 1A and 1B, when the second stripe-shaped isolation structure FG2 is an insulating isolation bar, the insulating isolation bar may serve as a support structure to support an electrode grid line between the negative terminal CF1 of a first sub-cell and the positive terminal CZ2 of an adjacent second sub-cell, and thus, various processes may be employed to normally form a second electrode grid line AG2 at the surface of the negative terminal CF1 of each first sub-cell and the positive terminal CZ2 of each second sub-cell. These processes include, but are not limited to, deposition processes, 3D printing processes, inkjet printing processes, screen printing processes, metal plating processes (e.g., copper plating processes, silver plating processes, etc.).

As shown in fig. 1A and 1B, when the second strip-shaped isolation structure FG2 is an isolation groove, there is a gap between the negative terminal CF1 of the first sub-cell and the positive terminal CZ2 of the adjacent second sub-cell. At this time, when the second electrode grid lines AG2 are normally formed on the surfaces of the positive terminals CZ1 of the first sub-cells and the negative terminals CF2 of the second sub-cells by a deposition process such as a sputtering process, the portions of the second electrode grid lines AG2 above the isolation grooves may be broken, and the solar cell may not be able to conduct current. In order to solve this problem, improvement may be made from two angles of the width of the second stripe isolation structure FG2 and the width of the second electrode gate line AG2, so as to reduce the possibility of the second electrode gate line AG2 breaking at a position above the second stripe isolation structure FG 2.

As shown in fig. 1A and 1B, the width of the second stripe-like isolation structure FG2 is less than 500 μm from the width of the second stripe-like isolation structure FG 2. At this time, the width of the second stripe-shaped isolation structure FG2 is relatively small. When the second stripe-shaped isolation structure FG2 is an isolation groove, a screen printing process, a printing process, or an electroplating process may be used to form the second kind of electrode grid line AG2 at the negative terminal CF1 of the first sub-cell and the positive terminal CZ2 of the second sub-cell at one time.

As shown in fig. 1A and 1B, when the negative terminal CF1 of the first sub-cell is connected to the positive terminal CZ2 of the second sub-cell through the corresponding electrode grid line, and the width of the second stripe-shaped isolation structure FG2 therebetween is less than or equal to 100 μm, the distance between the positive terminal CZ1 of the first sub-cell and the negative terminal CF2 of the second sub-cell is relatively small, so that when the first stripe-shaped isolation structure FG1 is an isolation groove, and the second electrode grid line AG2 is formed by a screen printing process, a printing process or an electroplating process, the second electrode grid line AG2 is relatively less likely to be broken at a portion above the isolation groove, thereby improving the connection reliability of the second electrode grid line AG 2.

As shown in fig. 1A and 1B, the width of the second electrode grid AG2 ranges from 20 μm to 200 μm, and may also range from 40 μm to 100 μm, in terms of the width of the second electrode grid AG 2. At this time, the width of the second electrode grid line AG2 not only can meet the requirement of current conduction, but also has a certain strength, so when the second strip-shaped isolation structure FG2 is an isolation groove, the second electrode grid line AG2 formed by a screen printing process, a printing process, or an electroplating process is not easily broken above the isolation groove, thereby improving the connection reliability of the second electrode grid line AG 2. Meanwhile, when the positive terminal CZ1 of the first sub-battery is connected with the negative terminal CF2 of the second sub-battery through the second electrode grid lines AG2, the number of the second electrode grid lines AG2 may range from 50 to 150, and may also range from 80 to 120. When the second stripe-shaped isolation structure FG2 is an isolation groove, the second electrode grid lines AG2 crossing over the isolation groove are multiple, so that one of the second electrode grid lines AG2 is broken due to insufficient supporting force of the isolation groove, and there may be another second electrode grid line AG2 to connect the first sub-cell in series with the adjacent second sub-cell.

In an alternative, as shown in fig. 1A and 2A, when each first Sub-cell and each second Sub-cell share the same silicon substrate Sub, the first Sub-cell and the second Sub-cell may be a silicon homojunction cell or a silicon heterojunction cell. Moreover, regardless of whether the first subcell and the second subcell are silicon homojunction cells or silicon heterojunction cells, the positive terminal CZ1 of each first subcell and the positive terminal CZ2 of each second subcell are P-doped layers, and the negative terminal CZ2 of each first subcell and the negative terminal CF2 of each second subcell are N-doped layers. The area difference between the P-type doped layer and the N-type doped layer can be 0.1% -10% according to the different solar cell technology routes.

When the first sub-cell and the second sub-cell are silicon heterojunction cells, a first intrinsic silicon layer is further arranged between the P-type doped layer and the silicon substrate, and a second intrinsic silicon layer is further arranged between the N-type doped layer and the silicon substrate. Certainly, a first transparent conducting layer is further formed on the surface, away from the first intrinsic silicon layer, of the P-type doped layer and used for collecting holes; and a second transparent conductive layer is formed on the surface of the N-type doped layer far away from the second intrinsic silicon layer and used for collecting electrons.

The first intrinsic silicon layer and the second intrinsic silicon layer may be intrinsic amorphous silicon thin films or intrinsic microcrystalline silicon thin films, etc., and the P-type doping layer may be a P-type amorphous silicon thin film or a P-type microcrystalline silicon thin film, etc. The N-type doped layer can be an N-type amorphous silicon film or an N-type microcrystalline silicon film. The first transparent conductive layer and the second transparent conductive layer may be made of one or more of Indium Tin Oxide (ITO), tungsten-doped indium oxide (In2O3: W, abbreviated as IWO), Indium Zinc Oxide (IZO), and titanium-doped indium oxide thin film (ITiO).

In practical applications, the thicknesses of the first intrinsic silicon layer and the second intrinsic silicon layer may be 5nm to 15nm, and the thicknesses of the N-type doped silicon layer and the N-type doped silicon layer may be 3nm to 10 nm. The thickness of the first transparent conductive layer and the second transparent conductive layer may be 50nm to 150 nm.

As shown in fig. 1A and 1B, when the silicon substrate Sub is a P-type crystalline silicon substrate, the P-type doped layer of the first Sub-cell may passivate the first surface I of the silicon substrate Sub, and reduce surface state defects of the silicon substrate Sub at the first surface I to reduce the recombination velocity of carriers. Similarly, the P-type doped layer of the second Sub-cell can passivate the second surface II of the silicon substrate Sub, and reduce surface state defects of the silicon substrate Sub on the second surface II to reduce the recombination velocity of carriers.

When the silicon substrate Sub is an N-type crystalline silicon substrate, the N-type doped layer of the first Sub-cell can serve as a back electric field. Similarly, the N-doped layer of the second sub-cell can act as a back electric field. The back electric field can effectively improve the collection efficiency of photon-generated carriers and improve the efficiency of the battery.

Fig. 9A to 9G illustrate schematic state diagrams of a manufacturing method of a solar cell provided by an embodiment of the present invention at various stages. The embodiment of the utility model provides a solar cell's preparation method includes:

as shown in FIG. 9A, an N-type monocrystalline silicon wafer c-Si is provided; and texturing and cleaning the N-type monocrystalline silicon wafer c-Si to enable the N-type monocrystalline silicon wafer c-Si to form a textured structure. The texture structure can be positioned on the front side of the N-type monocrystalline silicon piece c-Si, and can also be formed on the front side and the back side of the N-type monocrystalline silicon piece c-Si.

As shown in FIG. 9B, amorphous silicon materials are respectively deposited on the front side and the back side of the N-type monocrystalline silicon wafer c-Si, so that a first intrinsic amorphous silicon thin film i-Si-1 is formed on the front side of the N-type monocrystalline silicon wafer c-Si, and a second intrinsic amorphous silicon thin film i-Si-2 is formed on the back side of the N-type monocrystalline silicon wafer c-Si. The film thickness of the first intrinsic amorphous silicon thin film i-Si-1 and the second intrinsic amorphous silicon thin film i-Si-2 may be 5nm to 15 nm.

As shown in fig. 9C, the first intrinsic amorphous silicon thin film i-Si-1 may be divided into an isolation margin, a P-type formation region, and an N-type formation region according to a pattern design. The P-type forming regions and the N-type forming regions are alternately distributed, and isolation reserved regions are formed between the P-type forming regions and the N-type forming regions. And a first physical shielding structure MASK1 is adopted to shield the N-type forming region and the isolation reserved region, and a first P-type amorphous silicon layer P-Si-1 located in the P-type forming region is deposited on the first intrinsic amorphous silicon film i-Si-1, wherein the thickness of the first P-type amorphous silicon layer P-Si-1 is 3 nm-10 nm.

As shown in fig. 9D, the first physical MASK structure MASK1 is removed to expose the P-type formation region and the isolation reservation region, and then a second physical MASK structure MASK2 is formed in the P-type formation region and the isolation reservation region, and a first N-type amorphous silicon layer N-Si-1 having a thickness of 3nm to 10nm is deposited on the first intrinsic amorphous silicon film i-Si-1 in the N-type formation region; the second physical masking structure MASK2 is then removed, so that the first P-type amorphous silicon layer P-Si-1 and the isolation reserved region are exposed. At this time, the first P-type amorphous silicon layer P-Si-1 and the first N-type amorphous silicon layer N-Si-1 are alternately distributed. A strip-shaped gap corresponding to the isolation reserved area is formed between the first P-type amorphous silicon layer P-Si-1 and the first N-type amorphous silicon layer N-Si-1.

On this basis, as shown in FIG. 9E, a second P-type amorphous silicon layer P-Si-2 and a second N-type amorphous silicon layer N-Si-2 are deposited on the second intrinsic amorphous silicon thin film i-Si-2 in such a manner that a first P-type amorphous silicon layer P-Si-1 and a first N-type amorphous silicon layer N-Si-1 are deposited on the first intrinsic amorphous silicon thin film i-Si-1. The formed second P-type amorphous silicon layers P-Si-2 and the second N-type amorphous silicon layers N-Si-2 are alternately distributed. And a strip-shaped gap corresponding to the isolation reserved area is formed between the second P-type amorphous silicon layer P-Si-2 and the second N-type amorphous silicon layer N-Si-2. At this time, the second P-type amorphous silicon layer P-Si-2 is located right under the first P-type amorphous silicon layer P-Si-1. The second N-type amorphous silicon layer N-Si-2 is located right below the first P-type amorphous silicon layer P-Si-1.

As shown in FIG. 9F, a first ITO film TCO1 with the thickness of 60 nm-120 nm is magnetron sputtered on the first P-type amorphous silicon layer and the first N-type amorphous silicon layer N-Si-1 on the front side of the N-type monocrystalline silicon wafer c-Si, and a second ITO film TCO2 with the thickness of 60 nm-120 nm is magnetron sputtered on the second P-type amorphous silicon layer P-Si-2 and the second N-type amorphous silicon layer N-Si-2 on the back side of the N-type monocrystalline silicon wafer c-Si.

As shown in fig. 9F, if the number of sub-cells included in the solar cell is even, two kinds of external electrodes included in the solar cell may be simultaneously located on the back surface of the solar cell, i.e., formed on the second P-type amorphous silicon layer P-Si-2 and the second N-type amorphous silicon layer N-Si-2. At this time, an entire surface deposition process may be used to form an ITO material in the first P-type amorphous silicon layer P-Si-1 and the first N-type amorphous silicon layer N-Si-1 to form a first ITO thin film TCO 1. And forming an ITO material on the second P-type amorphous silicon layer P-Si-2 and the second N-type amorphous silicon layer N-Si-2 by adopting a physical shielding process, so that the ITO material is prevented from being formed in a strip gap between the second P-type amorphous silicon layer P-Si-2 and the second N-type amorphous silicon layer N-Si-2.

As shown in fig. 9G, an electrode grid line and an external electrode are printed on the first ITO film TCO1 and the second ITO film TCO2 by a screen printing process, and cured in a furnace at 200 ℃, thereby obtaining a solar cell. Table 1 is a list of exemplary film thicknesses for several solar cells provided by embodiments of the present invention.

Table 1 exemplary film thickness lists (unit: nm) for several solar cells provided by embodiments of the present invention

Examples of the invention

i-Si-1

p-Si-1

n-Si-1

TCO1

i-Si-2

p-Si-2

n-Si-2

TCO2

1

8nm

3nm

50nm

8nm

3nm

50nm

2

5nm

6nm

80nm

5nm

6nm

80nm

3

15nm

10nm

150nm

15nm

10nm

150nm

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

The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A solar cell, comprising a plurality of subcells, the plurality of subcells comprising: the first sub-battery and the second sub-battery are distributed alternately; each of the first subcells and each of the second subcells share a same silicon substrate having opposing first and second faces; the positive terminal of each of the first subcells and the negative terminal of each of the second subcells are located on the first face, and the negative terminal of each of the first subcells and the positive terminal of each of the second subcells are located on the second face;

the solar cell further comprises an electrode grid line; each first sub-battery and the adjacent second sub-battery are connected in series through the corresponding electrode grid line; when the electrode grid line is positioned on the first surface, one end of the electrode grid line is formed on the positive electrode end of the first sub-battery, and the other end of the electrode grid line is formed on the negative electrode end of the second sub-battery adjacent to the first sub-battery; when the electrode grid line is positioned on the second surface, one end of the electrode grid line is formed on the positive terminal of the second sub-battery, and the other end of the electrode grid line is formed on the negative terminal of the first sub-battery adjacent to the second sub-battery;

the solar cell also comprises two external electrodes which are formed on the two sub-cells positioned at the edges of the plurality of sub-cells.

2. The solar cell of claim 1, wherein a first strip-shaped isolation structure is arranged between the positive terminal of each first sub-cell and the negative terminal of the adjacent second sub-cell, and the width of the first strip-shaped isolation structure between the positive terminal of each first sub-cell and the negative terminal of the adjacent second sub-cell is less than or equal to 500 μm.

3. The solar cell of claim 2, wherein when the positive terminal of the first subcell is connected to the negative terminal of the second subcell through the corresponding electrode grid line, the width of the first striped isolation structure therebetween is less than or equal to 100 μ ι η; and/or the presence of a gas in the gas,

when the external electrode is positioned at the positive end of the first sub-battery or the negative end of the second sub-battery, the width of the first strip-shaped isolation structure adjacent to the sub-battery forming the external electrode is 10-500 micrometers.

4. The solar cell of claim 1, wherein a second strip-shaped isolation structure is arranged between the negative terminal of each first sub-cell and the positive terminal of the second sub-cell, and the width of the second strip-shaped isolation structure between the negative terminal of each first sub-cell and the positive terminal of each second sub-cell is less than or equal to 500 μm.

5. The solar cell according to claim 4, wherein when the negative terminal of the first sub-cell is connected to the positive terminal of the adjacent second sub-cell through the corresponding electrode grid line, the width of the second stripe-shaped isolation structure between the negative terminal of the first sub-cell and the positive terminal of the adjacent second sub-cell is less than or equal to 100 μm; and/or the presence of a gas in the gas,

when the external electrode is positioned at the negative end of the first sub-battery or the positive end of the second sub-battery, the width of the second strip-shaped isolation structure adjacent to the sub-battery forming the external electrode is 10-500 micrometers.

6. The solar cell according to any one of claims 1 to 5, wherein the positive terminal of each of the first subcells and the positive terminal of each of the second subcells are both P-type doped layers; and the negative electrode end of each first sub-battery and the negative electrode end of each second sub-battery are both N-type doped layers.

7. The solar cell of claim 6, wherein the first subcell and the second subcell are both heterojunction cells; a first intrinsic silicon layer is arranged between the P-type doped layer and the silicon substrate; and a second intrinsic silicon layer is also arranged between the N-type doped layer and the silicon substrate.

8. The solar cell of claim 7, wherein each electrode grid line is a screen printed electrode grid line, a printed grid line, or an electroplated grid line.

9. The solar cell according to any one of claims 1 to 5, wherein the total number of the first subcell and the second subcell is an even number, and two kinds of the external electrodes are located on the first surface or the second surface; or the like, or, alternatively,

the total number of the first sub-battery and the second sub-battery is an odd number, wherein one external connection electrode is located on the first surface, and the other external connection electrode is located on the second surface.

10. A photovoltaic module comprising the solar cell according to any one of claims 1 to 9; and two adjacent solar cells are interconnected through a solder strip.