Photovoltaic cell and photovoltaic cell assembly

Abstract

The utility model relates to a photovoltaic cell and a photovoltaic cell assembly. A photovoltaic cell comprises: a substrate having a light facing surface and a backlight surface which are oppositely arranged along a first direction, the first direction being a thickness direction of the substrate; the tunneling oxide layer is arranged on the backlight surface of the substrate; the doped polycrystalline silicon layer is arranged on one side, deviating from the substrate, of the tunneling oxide layer; the passivation structure comprises a barrier layer and a passivation layer group, and the barrier layer is stacked on the side, away from the tunneling oxide layer, of the doped polycrystalline silicon layer; wherein the passivation layer group is arranged on the side, away from the doped polycrystalline silicon layer, of the barrier layer in a stacked mode, and the passivation layer group comprises a hydrogen-containing passivation layer. The photovoltaic cell and the photovoltaic cell assembly can further improve the passivation performance.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic cell technology, and in particular to photovoltaic cells and photovoltaic cell modules. Background Art

[0002] As non-renewable energy sources such as coal and oil are frequently in short supply, energy issues have gradually become a bottleneck restricting social and economic development. Therefore, more and more countries have begun to develop solar energy resources to seek new impetus for economic development. In this environment, photovoltaic cells have a broader development prospect. At present, among various types of photovoltaic cells, tunneling oxide passivation cells (TOPCon) have gradually become one of the mainstream cells. However, although this type of cell has the advantages of tunneling oxide layer passivation contact, its passivation performance needs to be further improved under the current situation where the performance requirements of photovoltaic cells are increasing. Utility Model Content

[0003] Based on this, it is necessary to provide a photovoltaic cell and a photovoltaic cell assembly that can further improve the passivation performance.

[0004] A photovoltaic cell, comprising:

[0005] A substrate having a light-facing surface and a backlight surface arranged opposite to each other along a first direction, wherein the first direction is a thickness direction of the substrate;

[0006] A tunneling oxide layer is disposed on the backlight surface of the substrate;

[0007] A doped polysilicon layer is disposed on a side of the tunnel oxide layer away from the substrate;

[0008] A passivation structure, comprising a barrier layer and a passivation layer group, wherein the barrier layer stack is arranged on a side of the doped polysilicon layer away from the tunneling oxide layer, and the passivation layer group stack is arranged on a side of the barrier layer away from the doped polysilicon layer;

[0009] Wherein, the passivation layer group includes a hydrogen-containing passivation layer.

[0010] In one embodiment, the passivation layer group includes a plurality of hydrogen-containing passivation layers stacked along the first direction.

[0011] In one embodiment, among the multiple hydrogen-containing passivation layers, the refractive index of the hydrogen-containing passivation layer closest to the substrate is a, and the refractive index of the hydrogen-containing passivation layer farthest from the substrate is b;

[0012] Among them, a>b.

[0013] In one of the embodiments, the refractive index of the multiple layers of the hydrogen-containing passivation layer has a decreasing trend in a direction away from the substrate.

[0014] In one embodiment, among the multiple hydrogen-containing passivation layers, the refractive index of the hydrogen-containing passivation layer closest to the substrate is a;

[0015] Among them, 2.1≤a≤2.4.

[0016] In one embodiment, among the multiple hydrogen-containing passivation layers, the refractive index of the hydrogen-containing passivation layer farthest from the substrate is b;

[0017] Among them, 1.8≤b≤2.1.

[0018] In one of the embodiments, the thickness of the passivation layer group is d1, 70 nm≤d1≤90 nm.

[0019] In one embodiment, the barrier layer is a silicon oxide barrier layer, and the thickness is d2, 0.5nm≤d2≤8nm.

[0020] In one embodiment, the hydrogen-containing passivation layer is a hydrogen-containing silicon nitride layer, a hydrogen-containing silicon oxide layer or a hydrogen-containing silicon oxynitride layer.

[0021] A photovoltaic cell assembly, comprising a plurality of the above-mentioned photovoltaic cells;

[0022] The photovoltaic cell assembly also includes a frame, and a plurality of the photovoltaic cells are spliced ​​and installed in the frame.

[0023] The photovoltaic cell and photovoltaic cell assembly described above have a tunneling oxide layer and a doped polysilicon layer stacked in sequence on the backlight side of the substrate, and the two can passivate the substrate. At the same time, a barrier layer and a passivation layer group are stacked in sequence on the side of the doped polysilicon layer away from the tunneling oxide layer, and the passivation layer group includes a hydrogen-containing passivation layer. The hydrogen in the hydrogen-containing passivation layer can diffuse toward the substrate, and the hydrogen can saturate the unsaturated dangling bonds on the surface of the substrate when it reaches the substrate, and hydrogen passivates the substrate, further improving the passivation performance of the photovoltaic cell on the basis of the passivation of the tunneling oxide passivation structure (tunneling oxide layer and doped polysilicon layer). BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a schematic diagram of the structure of a photovoltaic cell in one embodiment of the present application.

[0025] FIG. 2 is a schematic structural diagram of a passivation structure in an embodiment of the present application.

[0026] Reference numerals:

[0027] 100, substrate; 110, light-facing surface; 120, backlight surface; 200, tunneling oxide layer; 300, doped polysilicon layer; 400, passivation structure; 410, barrier layer; 420, passivation layer group; 421, hydrogen-containing passivation layer; 500, front passivation layer; 600, front electrode; 700, back electrode. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0029] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0030] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0031] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0032] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0033] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0034] Referring to FIG. 1 and FIG. 2 , a photovoltaic cell provided in an embodiment of the present application includes a substrate 100, a tunneling oxide layer 200, a doped polysilicon layer 300 and a passivation structure 400. The substrate 100 has a light-facing surface 110 and a backlight surface 120 arranged opposite to each other along a first direction, and the first direction is the thickness direction of the substrate 100. The tunneling oxide layer 200 is arranged on the backlight surface 120 of the substrate 100. The doped polysilicon layer 300 is arranged on the side of the tunneling oxide layer 200 away from the substrate 100. The passivation structure 400 includes a barrier layer 410 and a passivation layer group 420. The barrier layer 410 is stacked and arranged on the side of the doped polysilicon layer 300 away from the tunneling oxide layer 200, and the passivation layer group 420 is stacked and arranged on the side of the barrier layer 410 away from the doped polysilicon layer 300. The passivation layer group 420 includes a hydrogen-containing passivation layer 421.

[0035] In the photovoltaic cell, a tunneling oxide layer 200 and a doped polysilicon layer 300 are sequentially stacked on the backlight surface of the substrate 100, and the two can passivate the substrate 100. At the same time, a barrier layer 410 and a passivation layer group 420 are sequentially stacked on the side of the doped polysilicon layer 300 away from the tunneling oxide layer 200, and the passivation layer group 420 includes a hydrogen-containing passivation layer 421. The hydrogen in the hydrogen-containing passivation layer 421 can diffuse toward the substrate 100, and after the hydrogen reaches the substrate 100, it can saturate the unsaturated dangling bonds on the surface of the substrate 100, and hydrogen passivate the substrate 100, further improving the passivation performance of the photovoltaic cell on the basis of the passivation of the tunneling oxide passivation structure (tunneling oxide layer 200 and doped polysilicon layer 300).

[0036] Specifically, the barrier layer 410 is used to block the diffusion of metal impurities toward the substrate 100, and the barrier layer 410 is used to allow hydrogen in the hydrogen-containing passivation layer 421 to pass through and diffuse toward the substrate 100. The barrier layer 410 can block the diffusion of metal impurities toward the substrate 100, that is, it is ensured that only hydrogen is passed through, but metal impurities are not passed through, so that the electrical performance of the photovoltaic cell is not reduced.

[0037] 1 and 2 , in some embodiments, the passivation layer group 420 includes a plurality of hydrogen-containing passivation layers 421 stacked along a first direction.

[0038] Specifically, multiple hydrogen-containing passivation layers 421 are stacked along the first direction on the side of the barrier layer 410 away from the doped polysilicon layer 300. The hydrogen in each hydrogen-containing passivation layer 421 can diffuse through the barrier layer 410 toward the substrate 100, and hydrogen passivate the substrate 100 to further improve the passivation performance of the photovoltaic cell.

[0039] 1 and 2 , in some embodiments, the hydrogen-containing passivation layer 421 is a hydrogen-containing silicon nitride layer, a hydrogen-containing silicon oxide layer, or a hydrogen-containing silicon oxynitride layer.

[0040] Specifically, in the multi-layer hydrogen-containing passivation layer 421, the material of each hydrogen-containing passivation layer 421 can be the same, for example, all are hydrogen-containing silicon nitride layers, hydrogen-containing silicon oxide layers, or hydrogen-containing silicon nitride oxide layers. Alternatively, in the multi-layer hydrogen-containing passivation layer 421, the material of each hydrogen-containing passivation layer 421 can be different, for example, part of the hydrogen-containing passivation layer 421 is a hydrogen-containing hydrogenated silicon nitride layer, part of the hydrogen-containing passivation layer 421 is a hydrogen-containing silicon oxide layer, and part of the hydrogen-containing passivation layer 421 is a hydrogen-containing silicon nitride oxide layer.

[0041] 1 and 2 , in some embodiments, among the multiple hydrogen-containing passivation layers 421 , the refractive index of the hydrogen-containing passivation layer 421 closest to the substrate 100 is a, and the refractive index of the hydrogen-containing passivation layer 421 farthest from the substrate 100 is b, and a>b.

[0042] Specifically, the "near" mentioned in the above description refers to the first formation in the manufacturing process, and the "far" refers to the later formation in the manufacturing process. Generally, the higher the refractive index, the higher the silicon content and the hydrogen content in the hydrogen-containing passivation layer 421, and the better the hydrogen passivation effect on the substrate 100. Therefore, setting the refractive index of the hydrogen-containing passivation layer 421 closest to the substrate 100 to be higher can further improve the passivation performance; at the same time, setting the refractive index of the hydrogen-containing passivation layer 421 farthest from the substrate 100 to be lower can have a better anti-reflection effect.

[0043] Referring to FIG. 1 and FIG. 2 , further, in some embodiments, in a direction away from the substrate 100 , the refractive index of the multi-layer hydrogen-containing passivation layer 421 has a decreasing trend.

[0044] Specifically, the refractive index of the multilayer hydrogen-containing passivation layer 421 gradually decreases in the direction away from the substrate 100. In this embodiment, the refractive index of the multilayer hydrogen-containing passivation layer 421 close to the substrate 100 is set higher, which can further improve the passivation performance; at the same time, the refractive index of the multilayer hydrogen-containing passivation layer 421 far from the substrate 100 is set lower, which can have a better anti-reflection effect.

[0045] 1 and 2 , in some embodiments, the refractive index of the hydrogen-containing passivation layer 421 closest to the substrate 100 among the multiple hydrogen-containing passivation layers 421 is a, 2.1≤a≤2.4. When this refractive index range is met, the hydrogen passivation effect on the substrate 100 will be better.

[0046] Furthermore, in some embodiments, 2.2≤a≤2.3. When this refractive index range is met, the hydrogen passivation effect on the substrate 100 will be better.

[0047] 1 and 2 , in some embodiments, the refractive index of the hydrogen-containing passivation layer 421 farthest from the substrate 100 among the multiple hydrogen-containing passivation layers 421 is b, 1.8≤b≤2.1. When this refractive index range is met, the anti-reflection effect will be better.

[0048] Furthermore, in some embodiments, 1.95≤b≤2.0. When this refractive index range is met, the anti-reflection effect will be better.

[0049] 1 and 2 , in some embodiments, when five hydrogen-containing passivation layers 421 are provided, in a direction away from the substrate 100 , the refractive indices of the five hydrogen-containing passivation layers 421 are 2.34%, 2.25%, 2.18%, 2.05%, and 1.96%, respectively.

[0050] Referring to FIG. 1 and FIG. 2 , in some embodiments, the thickness of the passivation layer group 420 is d1, 70nm≤d1≤90nm. Generally, the peak of the terrestrial solar spectrum energy is at a wavelength of 500nm, and the relative response peak of the photovoltaic cell is at a wavelength of 800nm-900nm. In this wavelength range, when the passivation layer group 420 is set to the above thickness range, the passivation effect is better.

[0051] Furthermore, in some embodiments, the thickness of the passivation layer group 420 is d1, where d1=80 nm. When the passivation layer group 420 is set to this thickness, the passivation effect is optimal.

[0052] 1 and 2 , in some embodiments, the thickness of the multi-layer hydrogen-containing passivation layer 421 gradually increases in a direction away from the substrate 100 .

[0053] Generally, the product of the thickness of the hydrogen-containing passivation layer 421 and its refractive index is a fixed value related to the wavelength, that is, the thickness of the hydrogen-containing passivation layer 421 is inversely proportional to its refractive index. As mentioned above, in the direction away from the substrate 100, the refractive index of the multilayer hydrogen-containing passivation layer 421 gradually decreases, which can further improve the passivation performance and have a better anti-reflection effect. Correspondingly, in the direction away from the substrate 100, the thickness of the multilayer hydrogen-containing passivation layer 421 will gradually increase.

[0054] 1 and 2 , in some embodiments, when five hydrogen-containing passivation layers 421 are provided, the thicknesses of the five hydrogen-containing passivation layers 421 in the direction away from the substrate 100 are 8-10 nm, 10-15 nm, 15-20 nm, 15-20 nm, and 20-30 nm, respectively.

[0055] 1 and 2, in some embodiments, the barrier layer 410 is a silicon oxide barrier layer. Silicon oxide can effectively block metal impurities from diffusing toward the substrate 100, that is, it ensures that only hydrogen passes through and reaches the substrate 100, but metal impurities do not pass through and reach the substrate 100, so that the electrical performance of the photovoltaic cell will not be reduced.

[0056] 1 and 2 , in some embodiments, the thickness of the barrier layer 410 is d2, and 0.5 nm≤d2≤8 nm.

[0057] Specifically, if the thickness of the barrier layer 410 is too large, hydrogen ions will be blocked from passing through, and hydrogen passivation of the substrate 100 cannot be completed; if the thickness of the barrier layer 410 is too small, although hydrogen ions can pass through, metal ions cannot be blocked from passing through, which will lead to reduced electrical performance of the photovoltaic cell. When the thickness of the barrier layer 410 is within the above range, hydrogen ions can be allowed to pass through while metal ions are blocked from passing through.

[0058] 1 , in some embodiments, a front passivation layer 500 is stacked on the light-facing surface 110 of the substrate 100. The front passivation layer 500 may be an aluminum oxide layer or a silicon nitride layer. The front passivation layer 500 may passivate the photovoltaic cell from the light-facing side.

[0059] 1 , in some embodiments, the photovoltaic cell includes a front electrode 600 and a back electrode 700 . The front electrode 600 is electrically connected to the substrate 100 through the front passivation layer 500 , and the back electrode 700 is electrically connected to the doped polysilicon layer 300 through the passivation structure 400 .

[0060] In some embodiments, the photovoltaic cell assembly includes a plurality of photovoltaic cells in any of the aforementioned embodiments, and also includes a frame, and the plurality of photovoltaic cells are spliced ​​and installed in the frame.

[0061] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A photovoltaic cell, characterized in that: The photovoltaic cell comprises: A substrate (100) having a light-facing surface (110) and a backlight surface (120) arranged opposite to each other along a first direction, wherein the first direction is a thickness direction of the substrate (100); A tunneling oxide layer (200) is disposed on the backlight surface (120) of the substrate (100); a doped polysilicon layer (300) disposed on a side of the tunneling oxide layer (200) facing away from the substrate (100); and A passivation structure (400), comprising a barrier layer (410) and a passivation layer group (420), wherein the barrier layer (410) is stacked and arranged on a side of the doped polysilicon layer (300) away from the tunneling oxide layer (200), and the passivation layer group (420) is stacked and arranged on a side of the barrier layer (410) away from the doped polysilicon layer (300); Wherein, the passivation layer group (420) includes a hydrogen-containing passivation layer (421).

2. The photovoltaic cell according to claim 1, characterized in that: The passivation layer group (420) includes a plurality of hydrogen-containing passivation layers (421) stacked along the first direction.

3. The photovoltaic cell according to claim 2, characterized in that: Among the multiple hydrogen-containing passivation layers (421), the refractive index of the hydrogen-containing passivation layer (421) closest to the substrate (100) is a, and the refractive index of the hydrogen-containing passivation layer (421) farthest from the substrate (100) is b; Among them, a>b.

4. The photovoltaic cell according to claim 3, characterized in that: In a direction away from the substrate (100), the refractive index of the multiple layers of the hydrogen-containing passivation layer (421) has a decreasing trend.

5. The photovoltaic cell according to claim 3, characterized in that: Among the multiple hydrogen-containing passivation layers (421), the hydrogen-containing passivation layer (421) closest to the substrate (100) has a refractive index a; Among them, 2.1≤a≤2.

4.

6. The photovoltaic cell according to claim 3, characterized in that: Among the multiple hydrogen-containing passivation layers (421), the refractive index of the hydrogen-containing passivation layer (421) farthest from the substrate (100) is b; Among them, 1.8≤b≤2.

1.

7. The photovoltaic cell according to any one of claims 1 to 6, characterized in that: The thickness of the passivation layer group (420) is d1, 70nm≤d1≤90nm.

8. The photovoltaic cell according to any one of claims 1 to 6, characterized in that: The barrier layer (410) is a silicon oxide barrier layer, and has a thickness d2, 0.5nm≤d2≤8nm.

9. The photovoltaic cell according to any one of claims 1 to 6, characterized in that: The hydrogen-containing passivation layer (421) is a hydrogen-containing silicon nitride layer, a hydrogen-containing silicon oxide layer or a hydrogen-containing silicon nitride oxide layer.

10. A photovoltaic cell assembly, characterized in that: The photovoltaic cell assembly comprises a plurality of photovoltaic cells as described in any one of claims 1 to 9; The photovoltaic cell assembly also includes a frame, and a plurality of the photovoltaic cells are spliced ​​and installed in the frame.

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