Heterojunction photovoltaic cell

Abstract

The utility model discloses a heterojunction photovoltaic cell, which comprises a heterojunction cell main body, two conductive films and a plurality of metal grid lines, and is characterized in that the heterojunction cell main body comprises an N-type silicon wafer and amorphous layers respectively arranged at two opposite ends of the N-type silicon wafer; the two conductive films are arranged at the ends, deviating from each other, of the two amorphous layers respectively, the ends, deviating from the corresponding amorphous layers, of the conductive films are arranged in a micro-concave point shape, and the multiple metal grid lines are arranged at the ends, deviating from each other, of the two conductive films respectively. And the plurality of metal grid lines arranged on the same conductive film are arranged at intervals along a first direction. Through the arrangement, the metal grid lines can have better adhesive force and stability, and meanwhile, the contact area between each conductive film and the corresponding metal grid line is also increased, so that the connection stability of the metal grid lines is further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic cells, in particular to a heterojunction photovoltaic cell sheet. Background Art

[0002] Under the dual passivation effect of N-type silicon substrate and amorphous silicon on substrate surface defects, the open circuit voltage of heterojunction cells is much higher than that of conventional cells, which is conducive to obtaining higher photoelectric conversion efficiency.

[0003] At present, heterojunction cells are a new type of cell process technology that uses thin film technology to produce PN junctions, anti-reflection layers and conductive layers on a crystalline silicon substrate. The process temperature of the entire front-end process of cell production does not exceed 400°C. Too high a temperature will cause great damage to the thin film structure of the heterojunction cell. Therefore, during metallization, only low-temperature silver paste can be used for printing. Based on the process, the temperature of the low-temperature silver paste needs to be controlled below 250°C. There is no silver powder sintering process, and the silver powders and the silver and the substrate are bonded by an organic resin phase.

[0004] However, when heterojunction cells are produced, silver paste is printed on the surface of the transparent conductive film TCO. Since low-temperature silver paste is used, the bonding strength between the conductive film TCO of the heterojunction cell and the silver paste is low, resulting in reduced long-term stability and adhesion of the silver paste. Utility Model Content

[0005] The main purpose of the utility model is to provide a heterojunction photovoltaic cell sheet, aiming to solve the problems of low bonding strength between the conductive film and the silver paste, and low long-term stability and adhesion of the silver paste in the existing heterojunction cell production process.

[0006] In order to achieve the above-mentioned purpose, the utility model proposes a heterojunction photovoltaic cell, comprising:

[0007] A heterojunction battery body, comprising an N-type silicon wafer and an amorphous layer disposed at two opposite ends of the N-type silicon wafer;

[0008] Two conductive films are disposed at ends of the two amorphous layers that are away from each other, and one end of each conductive film that is away from the corresponding amorphous layer is disposed in a micro-dimpled shape; and,

[0009] A plurality of metal grid lines are arranged at ends of the two conductive films which are away from each other, and the plurality of metal grid lines arranged on the same conductive film are spaced apart along the first direction.

[0010] Optionally, the ends of the two conductive films facing away from each other are each provided with a plurality of micro groove groups, the plurality of micro groove groups are respectively provided corresponding to the plurality of metal grid lines, and each of the micro groove groups includes a plurality of micro grooves spaced apart along the first direction and the second direction;

[0011] Each of the metal grid lines is at least partially located in a plurality of the micro grooves.

[0012] Optionally, a plurality of the micro grooves are arranged in an array.

[0013] Optionally, the plurality of micro grooves are arranged in a staggered manner.

[0014] Optionally, the shape of the notch of each of the micro grooves includes at least one of a circle, a square, a diamond, a triangle, a polygon, or an irregular shape.

[0015] Optionally, the cross-section of each of the micro grooves includes at least one of a rectangle, a semicircle, a trapezoid, or an irregular shape.

[0016] Optionally, the material of each of the metal grid lines includes silver.

[0017] In the technical solution provided by the utility model, the ends of the two conductive films that are opposite to each other are both arranged in the shape of micro-pits, and the multiple metal grid lines are arranged at the ends of the two conductive films that are arranged in the shape of micro-pits. In this arrangement, since each of the conductive films has an end face arranged in the shape of micro-pits, the roughness of the surface of each of the conductive films can be increased. When the multiple metal grid lines are printed on the corresponding conductive films, they can have better adhesion and stability. At the same time, the contact area between each of the conductive films and the corresponding metal grid lines is increased to further improve the stability of the metal grid line connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0019] Figure 1 A three-dimensional schematic diagram of an embodiment of a heterojunction photovoltaic cell provided by the utility model;

[0020] Figure 2 for Figure 1 A three-dimensional schematic diagram of an embodiment of a conductive film;

[0021] Figure 3 for Figure 1 A three-dimensional schematic diagram of another embodiment of the conductive film in FIG.

[0022] Description of Figure Numbers:

[0023] Label name Label name 100 Heterojunction photovoltaic cells 21 Micro groove 1 Heterojunction battery body 3 Metal grid 2 Conductive film

[0024] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0027] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0028] At present, the existing heterojunction battery is a new type of battery process technology that uses thin film technology to produce PN junctions, anti-reflection layers and conductive layers on a crystalline silicon substrate. The process temperature of the entire front-end process of battery production does not exceed 400°C. Too high a temperature will cause great damage to the thin film structure of the heterojunction battery. Therefore, during metallization, only low-temperature silver paste can be used for printing. Based on the process, the temperature of the low-temperature silver paste needs to be controlled below 250°C. There is no silver powder sintering process, and the silver powders and the silver and the substrate are bonded by an organic resin phase.

[0029] However, when heterojunction cells are produced, silver paste is printed on the surface of the transparent conductive film TCO. Since low-temperature silver paste is used, the bonding strength between the conductive film TCO of the heterojunction cell and the silver paste is low, resulting in reduced long-term stability and adhesion of the silver paste, which poses a high problem.

[0030] In order to solve the above problems, the utility model provides a heterojunction photovoltaic cell 100. Figures 1 to 3 This is a specific embodiment of the heterojunction photovoltaic cell provided by the utility model.

[0031] See also Figures 1 to 3 The heterojunction photovoltaic cell 100 includes a heterojunction cell body 1, two conductive films 2 and a plurality of metal grid lines 3. The heterojunction cell body 1 includes an N-type silicon wafer and an amorphous layer disposed at two opposite ends of the N-type silicon wafer. The two conductive films 2 are disposed at ends of the two amorphous layers that are opposite to each other, and the end of each conductive film 2 that is opposite to the corresponding amorphous layer is arranged in a micro-pit shape. The plurality of metal grid lines 3 are disposed at ends of the two conductive films 2 that are opposite to each other, and the plurality of metal grid lines 3 disposed on the same conductive film 2 are spaced apart along the first direction.

[0032] In the technical solution provided by the utility model, the ends of the two conductive films 2 that are opposite to each other are both arranged in the shape of micro-pits, and the multiple metal grid lines 3 are respectively arranged at the ends of the two conductive films 2 that are arranged in the shape of micro-pits. In this arrangement, since each of the conductive films 2 has an end face arranged in the shape of micro-pits, the roughness of the surface of each of the conductive films 2 can be increased. When the multiple metal grid lines 3 are printed on the corresponding conductive films 2, they can have better adhesion and stability. At the same time, the contact area between each of the conductive films 2 and the corresponding metal grid lines 3 is increased to further improve the stability of the connection of the metal grid lines 3.

[0033] It can be understood that when the ends of each conductive film 2 that are facing away from each other are arranged in a micro-dimpled shape, the contact area between each conductive film 2 and the corresponding metal grid line 3 will also increase, thereby reducing the resistance of each conductive film 2 and the corresponding metal grid line 3, thereby reducing the internal resistance consumption of the heterojunction photovoltaic cell 100 and improving the efficiency of the heterojunction photovoltaic cell 100.

[0034] It should be noted that the present invention does not limit the specific structural form of the end of the conductive film 2 that is arranged in a micro-dimpled shape. For example, in one embodiment of the present invention, a plurality of convex groups are convexly arranged at one end of each of the conductive films 2 that are away from each other, and the plurality of convex groups are respectively arranged corresponding to the plurality of metal grid lines 3, and each of the convex groups includes a plurality of convex parts arranged at intervals along the first direction and the second direction. Such an arrangement can increase the roughness of the end surface of each of the conductive films 2 that is away from the heterojunction battery body 1, and each of the metal grid lines 3 can wrap the plurality of convex parts, so that the metal grid lines 3 can have better adhesion and stability.

[0035] In another embodiment of the utility model, a plurality of micro grooves 21 groups are concavely arranged at one end of each of the conductive films 2 that are away from each other, and the plurality of micro grooves 21 groups are respectively arranged corresponding to the plurality of metal grid lines 3, and each of the micro grooves 21 groups includes a plurality of micro grooves 21 spaced apart along the first direction and the second direction, and each of the metal grid lines 3 is at least partially located in the plurality of micro grooves 21. In this way, the roughness of the end surface of each of the conductive films 2 that is away from the heterojunction battery body 1 can also be increased, and each of the metal grid lines 3 is at least partially located in the plurality of micro grooves 21, which can also make the metal grid lines 3 have better adhesion and stability, and increase the contact area between each of the conductive films 2 and the corresponding metal grid lines 3, thereby reducing the resistance of each of the conductive films 2 and the corresponding metal grid lines 3, so as to achieve the purpose of reducing the internal resistance consumption of the heterojunction photovoltaic cell 100 and improving the efficiency of the heterojunction photovoltaic cell 100.

[0036] Of course, in other embodiments of the utility model, a plurality of micro-grooves 21 groups and convex groups can be simultaneously arranged at one end of each conductive film 2 facing away from the heterojunction battery body 1, and each of the micro-grooves 21 groups and the convex groups corresponds to one metal grid line 3. At this time, the plurality of micro-grooves 21 in each micro-grooves 21 group and the plurality of convex parts in each convex part group are arranged in a staggered manner to jointly increase the roughness of the end surface of each conductive film 2 facing away from the heterojunction battery body 1, thereby improving the adhesion and stability of the metal grid line 3, and reducing the internal resistance consumption of the heterojunction photovoltaic cell 100, thereby improving the efficiency of the heterojunction photovoltaic cell 100. In actual settings, it can be selected according to needs.

[0037] In the utility model, when a plurality of micro-grooves 21 are recessed at one end of each conductive film 2 facing away from the heterojunction battery body 1, the plurality of micro-grooves 21 in each micro-groove 21 group are processed by laser processing. Specifically, the plurality of micro-grooves 21 are obtained by laser dotting.

[0038] It should be noted that the present invention does not limit the arrangement of the multiple microgrooves 21 in each microgroove group 21 or the arrangement of the multiple convex portions in each convex portion group. For example, when the end of each conductive film 2 facing away from the heterojunction battery body 1 is provided with multiple microgrooves 21 groups, the present invention does not limit the arrangement of the multiple microgrooves 21 in each microgroove group 21. In the first embodiment of the present invention, the multiple microgrooves 21 in each microgroove group 21 are arranged in an array. In this way, the spacing between two adjacent microgrooves 21 is equal, so that each part of the corresponding metal grid line 3 can have similar adhesion, thereby ensuring the stability of the metal grid line 3.

[0039] In the second embodiment of the utility model, the multiple micro-grooves 21 in each group of micro-grooves 21 are spaced apart in the first direction, and the two adjacent micro-grooves 21 in the second direction are staggered. Such an arrangement can also enable each part of the corresponding metal grid line 3 to have similar adhesion, thereby ensuring the stability of the metal grid line 3.

[0040] Of course, in the third embodiment of the present utility model, the plurality of micro-grooves 21 in each group of micro-grooves 21 may also be arranged at intervals in the second direction, and two adjacent micro-grooves 21 in the first direction may be arranged in a staggered manner.

[0041] In addition, in the fourth embodiment of the present utility model, the plurality of micro-grooves 21 in each group of micro-grooves 21 are arranged in a staggered manner. Specifically, in the present embodiment, the spacing between two adjacent micro-grooves 21 is different from each other. At this time, there is no regularity in the change of the distance between two adjacent ink dots. It is only necessary to ensure that each part of the corresponding metal grid line 3 is provided with the micro-grooves 21.

[0042] Similarly, the present invention does not limit the size of the multiple micro-grooves 21. In one embodiment of the present invention, the sizes of the multiple micro-grooves 21 in each group of micro-grooves 21 are set fairly, so that the adhesion of each metal grid line 3 can be similar, thereby ensuring the overall stability of the heterojunction photovoltaic cell 100.

[0043] In another embodiment of the present invention, the sizes of the plurality of micro-grooves 21 in different groups of the micro-grooves 21 may be different, so that the adhesion of the plurality of metal grid lines 3 may be different. In actual setting, the adjustment can be made according to the requirements of different metal grid lines 3 .

[0044] Of course, in another embodiment of the present invention, the sizes of the plurality of micro grooves 21 in each group of micro grooves 21 may be different from each other. Such a setting can also improve the adhesion of the corresponding metal grid lines 3, and can reduce the internal resistance consumption of the heterojunction photovoltaic cell 100, thereby improving the efficiency of the heterojunction photovoltaic cell 100. In actual setting, it can be selected according to the needs.

[0045] It is understandable that the present invention does not limit the specific shape of the notch of the micro groove 21, and the shape of the notch of each micro groove 21 includes at least one of a circle, a square, a diamond, a triangle, a polygon, or an irregular shape.

[0046] Of course, the shapes of the notches of the plurality of micro-grooves 21 in each group of micro-grooves 21 may also be different, and the present invention does not impose any limitation on this.

[0047] In addition, the present invention also does not limit the specific shape of the cross section of the micro groove 21, and the cross section of each micro groove 21 includes at least one of a rectangle, a semicircle, a trapezoid, or an irregular shape.

[0048] Furthermore, the cross-sectional shapes of the plurality of micro-grooves 21 in each group of micro-grooves 21 may also be different, and the present invention does not impose any limitation on this.

[0049] In this embodiment, the shapes of the notches of the plurality of micro grooves 21 are all set to be circular, and the shapes of the cross sections of the plurality of micro grooves 21 are all set to be semicircular, that is, in this embodiment, the shape of each micro groove 21 is a micro pit.

[0050] Furthermore, in order to further reduce the resistance between the metal grid lines 3 and the corresponding conductive film 2, thereby improving the efficiency of the heterojunction photovoltaic cell 100, the material of each of the metal grid lines 3 includes silver. It can be understood that setting the material of the metal grid lines 3 to silver can make the metal grid lines 3 have a lower resistivity, thereby reducing the internal resistance consumption of the heterojunction photovoltaic cell 100 and improving its efficiency.

[0051] At the same time, the material of the metal grid line 3 is set to silver, which will not cause excessively high material costs while improving the efficiency of the heterojunction photovoltaic cell 100.

[0052] Specifically, since the metal grid lines 3 are obtained by printing and coating the metal silver in a molten state, each of the conductive films 2 and the corresponding metal grid lines 3 are bonded and connected.

[0053] The above description is only a preferred embodiment of the utility model, and does not limit the patent scope of the utility model. All equivalent structural changes made by using the contents of the utility model specification and drawings under the concept of the utility model, or directly / indirectly used in other related technical fields are included in the patent protection scope of the utility model.

Claims

1. A heterojunction photovoltaic cell, characterized in that: include: A heterojunction battery body, comprising an N-type silicon wafer and an amorphous layer disposed at two opposite ends of the N-type silicon wafer; Two conductive films are disposed at ends of the two amorphous layers that are away from each other, and one end of each conductive film that is away from the corresponding amorphous layer is disposed in a micro-dimpled shape; and, A plurality of metal grid lines are arranged at ends of the two conductive films which are away from each other, and the plurality of metal grid lines arranged on the same conductive film are spaced apart along the first direction.

2. The heterojunction photovoltaic cell according to claim 1, characterized in that: A plurality of micro groove groups are formed at the ends of the two conductive films facing away from each other, and the plurality of micro groove groups are respectively arranged corresponding to the plurality of metal grid lines, and each of the micro groove groups includes a plurality of micro grooves arranged at intervals along the first direction and the second direction; Each of the metal grid lines is at least partially located in a plurality of the micro grooves.

3. The heterojunction photovoltaic cell according to claim 2, characterized in that: The plurality of micro grooves are arranged in an array.

4. The heterojunction photovoltaic cell according to claim 2, characterized in that: The plurality of micro grooves are arranged in a staggered manner.

5. The heterojunction photovoltaic cell according to claim 2, characterized in that: The shape of the notch of each of the micro grooves includes circle, square, diamond, triangle, and polygon.

6. The heterojunction photovoltaic cell according to claim 2, characterized in that: The cross section of each of the micro grooves includes a rectangle, a semicircle, or a trapezoid.

7. The heterojunction photovoltaic cell according to claim 1, characterized in that: The material of each of the metal grid lines includes silver.

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