Solar cell and solar cell module

Abstract

The application provides a solar cell and a solar cell module. The solar cell comprises a substrate, the substrate having a first surface; a first passivation layer, the first passivation layer being located on the first surface; a second passivation layer and a neutral layer, the second passivation layer being located on a side of the first passivation layer away from the substrate, and the first passivation layer and the second passivation layer comprising the neutral layer therebetween, the conductivity of the neutral layer being less than the conductivity of the first passivation layer, and the conductivity of the first passivation layer being less than the conductivity of the second passivation layer; a third passivation layer, the third passivation layer being located on the second passivation layer; a fourth passivation layer and a fifth passivation layer, the fourth passivation layer being located on the third passivation layer, and the fifth passivation layer being located on the fourth passivation layer. The solar cell and the solar cell module provided by the application can effectively prevent the potential-induced degradation (PID) effect, thereby further improving the performance of the cell.

Description

Technical Field

[0001] This application relates primarily to solar cell technology, and more particularly to a solar cell and a solar cell module. Background Technology

[0002] Driven by the goal of achieving "dual carbon" emissions reduction, the utilization of renewable energy has received widespread attention, and the photovoltaic industry has ushered in a better development opportunity. However, in actual use, due to the effect of potential-induced degradation (PID), photovoltaic modules face the problem of significant power degradation or even failure in a short period of time. For example, under high heat and humidity conditions (85°C / 85% humidity environment), when a very high negative voltage (-1000V) is applied to the module, the output power of the module decreases significantly over time.

[0003] Potential-Induced Degradation (PID) refers to the phenomenon where a high-intensity negative voltage is generated between a photovoltaic (PV) module and the ground, leading to a potential difference that causes a decrease in power generation efficiency. The direct harm of PID is the accumulation of a large amount of charge on the surface of the solar cells, deteriorating the passivation effect and resulting in a decrease in the fill factor, open-circuit voltage, and short-circuit current, ultimately causing a reduction in the overall output power of the PV module. Therefore, the PID effect poses a serious reliability risk in PV modules and PV power generation systems, and in severe cases, can cause rapid system power outages. Utility Model Content

[0004] The technical problem to be solved by this application is to provide a solar cell and solar cell module that can effectively prevent the PID effect, thereby further improving the performance of the cell.

[0005] To address the aforementioned technical problems, this application provides a solar cell, comprising: a substrate having a first surface; a first passivation layer located on the first surface; a second passivation layer and a neutralization layer, wherein the second passivation layer is located on the side of the first passivation layer away from the substrate, and a neutralization layer is included between the first passivation layer and the second passivation layer, the conductivity of the neutralization layer being less than the conductivity of the first passivation layer, and the conductivity of the first passivation layer being less than the conductivity of the second passivation layer; a third passivation layer, wherein a fourth passivation layer is located on the second passivation layer, and a fifth passivation layer is located on the third passivation layer.

[0006] Optionally, the first passivation layer comprises aluminum oxide, and the conductivity of the first passivation layer is in the range of 1×10⁻⁶. -12 S / cm~1×10 -14 S / cm, the negative charge density of the first passivation layer ranges from 0.6 × 10⁻⁶. 13 / cm2 ~6×10 13 / cm 2 .

[0007] Optionally, the refractive index of the second passivation layer is greater than 2.4, and the electrical conductivity of the second passivation layer is in the range of 1×10⁻⁶. -8 S / cm~1×10 -10 S / cm, the positive charge density of the second passivation layer is in the range of 10. 12 / cm 2 ~10 14 / cm 2 The thickness of the second passivation layer is greater than 10 nm.

[0008] Optionally, the refractive index of the neutralizing layer ranges from 1.25 to 1.4, and the electrical conductivity of the neutralizing layer ranges from 1 × 10⁻⁶. -14 S / cm~1×10 -16 S / cm, the negative charge density of the neutralization layer ranges from 1×10⁻⁶. 9 / cm 2 ~1×10 11 / cm 2 The thickness of the neutralizing layer ranges from 1 nm to 5 nm.

[0009] Optionally, the refractive index of the third passivation layer is less than that of the second passivation layer, the refractive index of the fourth passivation layer is less than that of the third passivation layer, and the refractive index of the fifth passivation layer is less than that of the fourth passivation layer.

[0010] Optionally, the refractive index of the third passivation layer is in the range of 1.9 to 2.1, the refractive index of the fourth passivation layer is in the range of 1.6 to 1.8, and the refractive index of the fifth passivation layer is in the range of 1.4 to 1.6.

[0011] Optionally, the charge density of the third passivation layer is in the range of 1×10⁻⁶. 12 / cm 2 ~1×10 14 / cm 2 The thickness of the third passivation layer ranges from 10 nm to 30 nm, the thickness of the fourth passivation layer ranges from 10 nm to 30 nm, and the thickness of the fifth passivation layer ranges from 10 nm to 30 nm.

[0012] Optionally, the substrate further includes a second surface opposite to the first surface, the first surface being closer to the sun than the second surface, and the solar cell further includes a tunneling oxide layer located on the second surface, with a doped polycrystalline silicon layer sequentially included on the side of the tunneling oxide layer away from the substrate.

[0013] Optionally, the solar cell further includes an emitter, a first metal electrode, and a second metal electrode, wherein the emitter is located within the substrate, the first metal electrode is electrically connected to the emitter, and the second metal electrode is electrically connected to the doped polycrystalline silicon layer.

[0014] Optionally, the first metal electrode is in contact with the emitter, and the substrate thickness of the contact portion of the first metal electrode within the substrate ranges from 0 nm to 100 nm.

[0015] To address the aforementioned technical problems, this application provides a solar cell module, comprising one or more solar cells as described above.

[0016] Compared with the prior art, this application provides a neutralization layer between the first passivation layer and the second passivation layer, and sets the conductivity of the neutralization layer to be lower than that of the first passivation layer. Furthermore, it sets the conductivity of the first passivation layer to be lower than that of the second passivation layer. This allows the neutralization layer to isolate the first passivation layer and the second passivation layer, preventing metal recombination between them. This further prevents the PID effect and improves battery performance. Attached Figure Description

[0017] The accompanying drawings are included to provide a further understanding of this application; they are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application. In the drawings:

[0018] Figure 1 This is a schematic diagram of the film structure of a solar cell according to one embodiment of this application;

[0019] Figure 2 This is one embodiment of the present application that employs, as follows Figure 1 The diagram shows the overall structure of a solar cell with a film layer structure. Detailed Implementation

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0021] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0022] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0023] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0024] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0025] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0026] This application refers to Figure 1 A solar cell 10 is proposed, which mainly includes a substrate 11, a first passivation layer 12, a neutralization layer 13, a second passivation layer 14, a third passivation layer 15, a fourth passivation layer 16, and a fifth passivation layer 17. See the specific reference. Figure 1 The substrate 11 has a first surface S1 and a second surface S2 opposite to the first surface S1, wherein the first surface S1 is closer to the sun than the second surface S2. For example, the substrate 11 is a silicon substrate. The outer surface of the fifth passivation layer 17 can be the light-facing surface of the solar cell 10.

[0027] Furthermore, the first passivation layer 12 is located on the first surface S1, the second passivation layer 14 is located on the side of the first passivation layer 12 away from the substrate 11, and a neutralization layer 13 is included between the first passivation layer 12 and the second passivation layer 14. The conductivity of the neutralization layer 13 is less than the conductivity of the first passivation layer 12, and the conductivity of the first passivation layer 12 is less than the conductivity of the second passivation layer 14.

[0028] In this preferred embodiment, the first passivation layer 12 comprises aluminum oxide, the second passivation layer 14 comprises silicon nitride, and the neutralization layer 13 comprises a dense, transparent material, such as magnesium fluoride. The conductivity of the first passivation layer 12 is in the range of 1×10⁻⁶. -12 S / cm~1×10 -14 S / cm, the conductivity of the second passivation layer 14 is in the range of 1×10. -8 S / cm~1×10 -10 The conductivity of neutralizing layer 13 is 1×10⁻⁶ S / cm. -14 S / cm~1×10 -16 S / cm, the negative charge density of the neutralization layer ranges from 1×10 9 / cm 2 ~1×10 11 / cm 2 The thickness of the neutralization layer ranges from 1 nm to 5 nm. It can be seen that in the solar cell 10, the conductivity of the neutralization layer 13 is less than that of the first passivation layer 12, and the conductivity of the first passivation layer 12 is less than that of the second passivation layer 14. This means that the neutralization layer 13 has the lowest conductivity and can effectively play an insulating role.

[0029] Furthermore, the negative charge density in the aluminum oxide of the first passivation layer 12 ranges from 0.6 × 10⁻⁶. 13 / cm 2 ~6×10 13 / cm 2 This means that the first passivation layer 12 has a dense negative charge, while the positive charge density of the second passivation layer 14 ranges from 10. 12 / cm 2 ~10 14 / cm 2 This means that silicon nitride carries a large amount of positive charge. By setting a neutralizing layer 13 with very low conductivity and near-insulation between the first passivation layer 12 and the second passivation layer 14, the charge can be transferred during the loading process, thereby greatly reducing the possibility of metal recombination at the interface between the first passivation layer 12 and the second passivation layer 14, and blocking the possibility of charge neutralization between the first passivation layer 12 and the second passivation layer 14, thus achieving the effect of resisting PID effect. For example, the refractive index of the second passivation layer 14 is greater than 2.4, the thickness of the second passivation layer 14 is greater than 10 nm, and the refractive index of the neutralizing layer 13 is in the range of 1.25 to 1.4, and the thickness of the neutralizing layer 13 is in the range of 1 nm to 5 nm.

[0030] In this embodiment, Table 1 shows the degradation data of various battery parameters of the existing battery structure after a 192-hour PID effect experiment, and Table 2 shows the degradation data of various battery parameters of the solar cell 10 after a 192-hour PID effect experiment. As can be seen from the tables, the degradation of solar cell 10 in terms of power, open-circuit voltage, short-circuit current, fill factor, voltage at maximum power, and current at maximum power after 192 hours of PID is less than that of the existing battery structure. This means that solar cell 10 can effectively prevent the PID effect, thereby further improving battery performance.

[0031] Table 1. PID attenuation data of existing battery structure over 192 hours

[0032]

[0033] Table 2. Solar cell degradation data after 192 hours of PID (Polymerization Process)

[0034]

[0035] On the other hand, while adding neutralization layer 13 significantly reduces degradation, the overall electrical performance of solar cell 10 remains unchanged. Table 3 shows a comparison of the electrical performance of existing cell structures (without neutralization layer 13) and solar cell 10, where efficiency, on-state current, short-circuit current, fill factor, series resistance, parallel resistance, and dark current reflect the electrical performance of the solar cell. As can be seen from the table, the electrical performance of solar cell 10 is basically the same as that of the existing cell structure (without neutralization layer 13). This means that adding neutralization layer 13 to the cell structure can significantly reduce degradation and stabilize the cell's electrical performance, resulting in better and superior performance for the solar cell.

[0036] Table 3. Electrical performance comparison data

[0037] Battery efficiency Open pressure short circuit current Fill factor Series resistor Parallel resistors Dark current Existing battery structure 26.22 734.54 16.053 85.04 0.6713 2909 0.037 Solar cell 10 26.23 734.28 16.065 85.03 0.6865 3014 0.04

[0038] Furthermore, in this embodiment, the third passivation layer 15 of the solar cell 10 is located on the second passivation layer 14, the fourth passivation layer 16 is located on the third passivation layer 15, and the fifth passivation layer 17 is located on the fourth passivation layer 16. The refractive index of the third passivation layer 15 is in the range of 1.9 to 2.1, the refractive index of the fourth passivation layer 16 is in the range of 1.6 to 1.8, and the refractive index of the fifth passivation layer 17 is in the range of 1.4 to 1.6. For example, the third passivation layer comprises silicon nitride with a refractive index in the range of 1.9 to 2.1, the fourth passivation layer 16 comprises silicon oxynitride with a refractive index in the range of 1.6 to 1.8, and the fifth passivation layer 17 comprises silicon oxide with a refractive index in the range of 1.4 to 1.6.

[0039] Preferably, in this embodiment, the refractive index of the third passivation layer 15 is less than that of the second passivation layer 14, the refractive index of the fourth passivation layer 16 is less than that of the third passivation layer 15, and the refractive index of the fifth passivation layer 17 is less than that of the fourth passivation layer 16. In the solar cell 10, since the refractive index of the second passivation layer is greater than 2.4, its extinction coefficient is 40% in the short-wavelength range of 250nm to 400nm. By setting the refractive index of the third passivation layer 15, the fourth passivation layer 16, and the fifth passivation layer 17 to be less than that of the fourth passivation layer 16, a good optical path can be provided for the solar cell, reducing the current loss caused by the high extinction coefficient of the second passivation layer 14. For example, the charge density of the third passivation layer is in the range of 1×10⁻⁶. 12 / cm 2 ~1×10 14 / cm 2 The thickness of the third passivation layer ranges from 10 nm to 30 nm, the thickness of the fourth passivation layer ranges from 10 nm to 30 nm, and the thickness of the fifth passivation layer ranges from 10 nm to 30 nm.

[0040] The back side of the solar cell 10 also includes a tunneling oxide layer 22, which is located on the second surface S2. On the side of the tunneling oxide layer 22 away from the substrate 11, a doped polycrystalline silicon layer 23 and an anti-reflection layer 24 are sequentially included. The solar cell 10 further includes an emitter 25, a first metal electrode 26, and a second metal electrode 27. The emitter 25 is located inside the substrate 11. The first metal electrode 26 is in direct contact with the emitter 25, i.e., the first metal electrode 26 is electrically connected to the emitter 25. The second metal electrode 27 is in direct contact with the doped polycrystalline silicon layer 23, i.e., the second metal electrode 27 is electrically connected to the doped polycrystalline silicon layer 23.

[0041] Preferably, in this application, the first metal electrode 26 is in direct contact with the emitter 25. This means that in the solar cell 10 provided in this application, the first metal electrode 26 extends all the way into the interior of the substrate 11. Figure 1 As shown, the thickness x of the contact portion of the first metal electrode 26 located in the substrate 11 ranges from 0 nm to 100 nm, for example, 0 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm and 100 nm.

[0042] Furthermore, to better understand the above structure, the fabrication process of the 10-layer film in solar cells is briefly described below:

[0043] First, a silicon substrate needs to be prepared, and an aluminum oxide film with a thickness of 1nm to 3nm needs to be deposited on the first surface of the silicon substrate using PECVD.

[0044] Secondly, a magnesium fluoride layer is deposited on the alumina film by evaporation and vapor deposition to ensure that the thickness of the magnesium fluoride layer is between 1 nm and 5 nm.

[0045] Next, a second passivation layer 14, i.e. a high refractive index silicon nitride layer with a refractive index greater than 2.4, was prepared on the magnesium fluoride film using PECVD.

[0046] Finally, a low-refractive-index silicon nitride layer, a silicon oxynitride film, and a silicon oxide layer with a refractive index of 1.9 to 2.1 are sequentially deposited on the high-refractive-index silicon nitride layer using PECVD.

[0047] In another aspect, this application also proposes a solar cell assembly comprising one or more solar cells as described above, such as solar cell 10.

[0048] This application provides a neutralization layer between the first passivation layer and the second passivation layer, and sets the conductivity of the neutralization layer to be lower than that of the first passivation layer. Furthermore, it sets the conductivity of the first passivation layer to be lower than that of the second passivation layer. This allows the neutralization layer to isolate the first passivation layer and the second passivation layer, preventing metal recombination between them and further preventing the PID effect, thereby improving battery performance.

[0049] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0050] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0051] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the present application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0052] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0053] Although this application has been described with reference to specific embodiments, those skilled in the art should recognize that the above embodiments are only used to illustrate this application, and various equivalent changes or substitutions can be made without departing from the spirit of this application. Therefore, any changes or modifications to the above embodiments within the essential spirit of this application will fall within the scope of the claims of this application.

Claims

1. A solar cell, characterized in that, include: Substrate, the substrate having a first surface; A first passivation layer is located on the first surface; A second passivation layer and a neutralization layer are provided. The second passivation layer is located on the side of the first passivation layer away from the substrate, and a neutralization layer is provided between the first passivation layer and the second passivation layer. The conductivity of the neutralization layer is less than that of the first passivation layer, and the conductivity of the first passivation layer is less than that of the second passivation layer. A third passivation layer is located on top of the second passivation layer; A fourth passivation layer and a fifth passivation layer, wherein the fourth passivation layer is located on the third passivation layer and the fifth passivation layer is located on the fourth passivation layer.

2. The solar cell of claim 1, wherein, The first passivation layer comprises aluminum oxide, and the conductivity of the first passivation layer is in the range of 1×10⁻⁶. -12 S / cm~1×10 -14 S / cm, the negative charge density of the first passivation layer ranges from 0.6 × 10⁻⁶. 13 / cm 2 ~6×10 13 / cm 2 .

3. The solar cell as described in claim 1, characterized in that, The refractive index of the second passivation layer is greater than 2.4, and the electrical conductivity of the second passivation layer is in the range of 1×10⁻⁶. -8 S / cm~1×10 -10 S / cm, the positive charge density of the second passivation layer is in the range of 10. 12 / cm 2 ~10 14 / cm 2 The thickness of the second passivation layer is greater than 10 nm.

4. The solar cell as described in claim 1, characterized in that, The refractive index of the neutralizing layer ranges from 1.25 to 1.4, and the electrical conductivity of the neutralizing layer ranges from 1 × 10⁻⁶. -14 S / cm~1×10 -16 S / cm, the negative charge density of the neutralization layer ranges from 1×10⁻⁶. 9 / cm 2 ~1×10 11 / cm 2 The thickness of the neutralizing layer ranges from 1 nm to 5 nm.

5. The solar cell as described in claim 1, characterized in that, The refractive index of the third passivation layer is less than that of the second passivation layer, the refractive index of the fourth passivation layer is less than that of the third passivation layer, and the refractive index of the fifth passivation layer is less than that of the fourth passivation layer.

6. The solar cell as described in claim 5, characterized in that, The refractive index of the third passivation layer ranges from 1.9 to 2.1, the refractive index of the fourth passivation layer ranges from 1.6 to 1.8, and the refractive index of the fifth passivation layer ranges from 1.4 to 1.

6.

7. The solar cell according to claim 1, characterized in that, The charge density range of the third passivation layer is 1×10⁻⁶. 12 / cm 2 ~1×10 14 / cm 2 The thickness of the third passivation layer ranges from 10 nm to 30 nm, the thickness of the fourth passivation layer ranges from 10 nm to 30 nm, and the thickness of the fifth passivation layer ranges from 10 nm to 30 nm.

8. The solar cell as claimed in claim 1, characterized in that, The substrate further includes a second surface opposite to the first surface, the first surface being closer to the sun than the second surface, and the solar cell further includes a tunneling oxide layer located on the second surface, with a doped polycrystalline silicon layer sequentially included on the side of the tunneling oxide layer away from the substrate.

9. The solar cell as described in claim 8, characterized in that, It also includes an emitter, a first metal electrode, and a second metal electrode. The emitter is located within the substrate, the first metal electrode is electrically connected to the emitter, and the second metal electrode is electrically connected to the doped polycrystalline silicon layer.

10. The solar cell as claimed in claim 9, characterized in that, The first metal electrode is in contact with the emitter, and the substrate thickness of the contact portion of the first metal electrode within the substrate ranges from 0 nm to 100 nm.

11. A solar cell module, characterized in that, It includes one or more solar cells as described in claims 1 to 10.

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