CN219800864U - Solar cell, cell module and photovoltaic system - Google Patents

Abstract

The utility model is suitable for the technical field of solar cells, and provides a solar cell, a cell module and a photovoltaic system. Therefore, the carbon nitride film layer has better chemical inertia and stability and high-quality light transmittance, and the PID resistance of the solar cell can be improved while the passivation effect is ensured by introducing the carbon nitride film layer on the silicon nitride film layer, so that the solar cell has good PID resistance effect.

Description

Solar cell, cell module and photovoltaic system

Technical Field

The utility model relates to the technical field of solar cells, in particular to a solar cell, a cell assembly and a photovoltaic system.

Background

Currently, the back passivation structure of existing solar cells (e.g., solar cells) typically deposits an aluminum oxide layer, a silicon oxide layer, and one or more silicon nitride layers on the back of the substrate in order to achieve back passivation. However, in such a solution, although many hydrogen (H) ions exist in the silicon nitride, dangling bonds in the battery can be passivated to reduce recombination, but the anti-PID effect of the battery sheet is limited. Therefore, how to further improve the PID resistance of the solar cell becomes a technical problem for research by the skilled person.

Disclosure of Invention

The utility model provides a solar cell, a cell assembly and a photovoltaic system, and aims to solve the technical problem of how to further improve the PID resistance of the solar cell.

The solar cell comprises a substrate and a back film layer structure which is laminated on the back surface of the substrate, wherein the back film layer structure comprises an aluminum oxide film layer, a silicon nitride film layer and a carbon nitride film layer which are laminated on the back surface of the substrate in sequence.

Further, the thickness of the carbon nitride film layer is 13nm-20nm.

Further, the thickness of the alumina film layer is 8nm-12nm.

Further, the thickness of the silicon oxide film layer is 4nm-10nm.

Further, the silicon nitride film layer is a composite film layer, and the silicon nitride film layer comprises at least two silicon nitride films which are arranged along the direction of the front surface of the substrate towards the back surface of the substrate and sequentially reduce the refractive index.

Further, the silicon nitride film layer comprises a top layer silicon nitride film and a bottom layer silicon nitride film, wherein the top layer silicon nitride film is arranged on the silicon oxide film layer in a laminated mode, the bottom layer silicon nitride film is arranged on the top layer silicon nitride film in a laminated mode, the refractive index of the top layer silicon nitride film is 2.13-2.15, and the refractive index of the bottom layer silicon nitride film is 2.10-2.13.

Further, the thickness of the top silicon nitride film is 20nm-26nm.

Further, the thickness of the underlying silicon nitride film is 22nm-28nm.

The utility model also provides a battery assembly which comprises a plurality of solar cells.

The utility model also provides a photovoltaic system which comprises the battery assembly.

In the solar cell, the cell module and the photovoltaic system provided by the embodiment of the utility model, the passivation film layer on the back surface of the solar cell is an aluminum oxide film layer, a silicon nitride film layer and a carbon nitride film layer which are sequentially stacked. Therefore, the carbon nitride film layer has better chemical inertia and stability and high-quality light transmittance, and the PID resistance of the solar cell can be improved while the passivation effect is ensured by introducing the carbon nitride film layer on the silicon nitride film layer, so that the solar cell has good PID resistance effect.

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

Drawings

Fig. 1 is a schematic structural diagram of a photovoltaic system according to an embodiment of the present utility model;

fig. 2 is a schematic structural view of a battery assembly according to an embodiment of the present utility model;

fig. 3 is a schematic structural diagram of a solar cell according to an embodiment of the present utility model;

FIG. 4 is a schematic structural view of a backside film structure provided in an embodiment of the present utility model;

fig. 5 is another schematic structural diagram of a solar cell according to an embodiment of the present utility model;

fig. 6 is another schematic structural view of a backside film layer structure according to an embodiment of the present utility model.

Description of main reference numerals:

photovoltaic system 1000, cell assembly 200, solar cell 100, substrate 10, back side film structure 20, aluminum oxide film 21, silicon oxide film 22, silicon nitride film 23, top layer silicon nitride film 231, bottom layer silicon nitride film 232, carbon nitride film 24, front side film structure 30, back side electrode 40, front side electrode 50.

Detailed Description

The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent. Examples of the embodiments are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements throughout or elements having like or similar functionality. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the utility model. Furthermore, it should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the present utility model.

In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "top", "bottom", etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the device or element in question must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

In the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically connected, electrically connected or can be communicated with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

The following disclosure provides many different embodiments, or examples, for implementing different structures of the utility model. In order to simplify the present disclosure, components and arrangements of specific examples are described below. They are, of course, merely examples and are not intended to limit the utility model. Furthermore, the present utility model may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present utility model provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize applications of other processes and/or usage scenarios for other materials.

According to the utility model, the carbon nitride film layer is introduced into the back film layer structure of the solar cell, so that the carbon nitride film layer has good chemical inertia, stability and high-quality light transmittance, and the PID resistance of the solar cell can be improved while the passivation effect is ensured, so that the solar cell has good PID resistance.

Example 1

Referring to fig. 1 and 2, a photovoltaic system 1000 according to an embodiment of the present utility model may include a battery assembly 200 according to an embodiment of the present utility model, the battery assembly 200 according to an embodiment of the present utility model may include a plurality of solar cells 100 according to an embodiment of the present utility model, and the solar cells 100 may be PERC solar cells.

Referring to fig. 3 and 4, the solar cell 100 according to the embodiment of the present utility model may include a substrate 10 and a back surface film structure 20 stacked on the back surface of the substrate 10, wherein the back surface film structure 20 includes an aluminum oxide film layer 21, a silicon oxide film layer 22, a silicon nitride film layer 23, and a carbon nitride film layer 24 stacked on the back surface of the substrate 10 in this order.

That is, the aluminum oxide film layer 21 may be stacked on the back surface of the substrate 10, the silicon oxide film layer 22 is stacked on the aluminum oxide film layer 21, the silicon nitride film layer 23 is stacked on the silicon oxide film layer 22, and the carbon nitride film layer 24 is stacked on the silicon nitride film layer 23.

In the solar cell 100, the cell module 200 and the photovoltaic system 1000 according to the embodiment of the present utility model, the passivation film layer on the back surface of the solar cell 100 is an aluminum oxide film layer 21, a silicon oxide film layer 22, a silicon nitride film layer 23 and a carbon nitride film layer 24, which are sequentially stacked. Thus, the carbon nitride film layer 24 has better chemical inertness and stability and high-quality light transmittance, and the PID resistance of the solar cell 100 can be improved while the passivation effect is ensured by introducing the carbon nitride film layer 24 on the silicon nitride film layer 23, so that the solar cell 100 has good PID resistance effect.

Meanwhile, the carbon nitride film 24 does not contain silicon element, so that the silicon element does not react with electrodes subjected to subsequent printing and sintering, the recombination can be effectively reduced, and the efficiency of the solar cell 100 can be improved.

Specifically, in the embodiment of the present utility model, the substrate 10 may be manufactured by a process of texturing, diffusing, etc. a silicon wafer may be a monocrystalline silicon wafer or a polycrystalline silicon wafer, which is not limited herein. In some embodiments, the front side of the substrate 10 may be formed with a textured structure, i.e., the silicon wafer may be diffused and textured to form the substrate 10 with a textured structure.

Referring to fig. 5, in the embodiment of the present utility model, a front surface film layer structure 30 may be further disposed on the front surface of the substrate 10, where the front surface film layer structure 30 may be used for passivating the front surface of the substrate 10, and the front surface film layer structure 30 may include a silicon nitride film, a silicon oxide film and a silicon nitride film that are sequentially stacked, or may include a silicon oxide film, a silicon nitride film, a silicon oxynitride film layer, and the like that are sequentially stacked, and the specific structure of the front surface film layer structure 30 is not limited, and only needs to be capable of passivating the front surface of the substrate 10.

Of course, referring to fig. 5, it will be appreciated that in embodiments of the present utility model, the solar cell 100 may further include a back electrode 40 that forms an ohmic structure with the substrate 10 through the back surface film layer structure 20 and a front electrode 50 that forms an ohmic contact with the substrate 10 through the front surface film layer structure 30.

In some embodiments, the back electrode 40 and the front electrode 50 may be metal electrodes, for example, the back electrode 40 may be an aluminum electrode, and since the back film layer 24 in the back film layer structure 20 has no silicon element, the carbon film layer 24 will not react with aluminum paste when sintering the back aluminum electrode, so that the corresponding recombination can be effectively reduced, and the efficiency of the solar cell 100 can be improved.

Specifically, the back electrode 40 may be formed by screen printing and sintering after laser grooving on the back film layer structure 20, and the front electrode 50 may be formed by screen printing and sintering after laser grooving on the front film layer structure 30.

In an embodiment of the present utility model, the plurality of solar cells 100 in the battery assembly 200 may be serially connected or connected in parallel in order to form a battery string, so as to realize serial or parallel bus output of current, for example, serial and parallel connection of the cells may be realized by providing a welding strip.

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

The photovoltaic glass may be coated on the adhesive film on the front surface of the solar cell sheet 100, and the photovoltaic glass may be ultra-white glass having high light transmittance, high transparency, and excellent physical, mechanical, and optical properties, for example, the ultra-white glass may have a light transmittance of 80% or more, which may protect the solar cell sheet 100 without affecting the efficiency of the solar cell sheet 100 as much as possible. Meanwhile, the photovoltaic glass and the solar cell sheet 100 can be bonded together by the adhesive film, and the solar cell sheet 100 can be sealed and insulated and waterproof and moistureproof by the adhesive film.

The back plate can be attached to the adhesive film on the back of the solar cell 100, can protect and support the solar cell 100, has reliable insulativity, water resistance and aging resistance, can be selected multiple times, and can be toughened glass, organic glass, an aluminum alloy TPT composite adhesive film and the like, and the back plate can be specifically set according to specific conditions without limitation. The whole of the back plate, the solar cell 100, the adhesive film and the photovoltaic glass may be disposed on a metal frame, which serves as a main external support structure of the entire battery assembly 200, and may stably support and mount the battery assembly 200, for example, the battery assembly 200 may be mounted at a desired mounting position through the metal frame.

Further, in the present utility model, the photovoltaic system 1000 may be applied to a photovoltaic power station, such as a ground power station, a roof power station, a water power station, etc., and may also be applied to a device or apparatus for generating electricity using solar energy, such as a user solar power source, a solar street lamp, a solar car, a solar building, etc. Of course, it is understood that the application scenario of the photovoltaic system 1000 is not limited thereto, that is, the photovoltaic system 1000 may be applied in all fields where solar energy is required to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system 1000 may include a photovoltaic array, a junction box and an inverter, where the photovoltaic array may be an array combination of a plurality of battery assemblies 200, for example, a plurality of battery assemblies 200 may form a plurality of photovoltaic arrays, the photovoltaic array is connected to the junction box, the junction box may junction currents generated by the photovoltaic array, and the junction box may convert the junction currents into alternating currents required by a utility power network through the inverter, and then access the utility power network to realize solar power supply.

Example two

Further, in some embodiments, the thickness of the carbon nitride film 24 may be 13nm-20nm.

Thus, by setting the thickness of the carbon nitride film 24 within this reasonable range, it is possible to avoid the carbon nitride film 24 being too thick to affect the subsequent laser grooving process, and also to avoid the carbon nitride film 24 being too thin to affect the passivation effect.

Specifically, in such embodiments, the thickness of the carbon nitride film 24 may be, for example, 13nm, 14nm, 15nm, 16nm, 17nm, 18nm, 19nm, 20nm, or any value between 13nm and 20nm, particularly without limitation herein.

Example III

In some embodiments, the thickness of the aluminum oxide film layer 21 may be 8nm-12nm.

Thus, by setting the thickness of the aluminum oxide film layer 21 within the above-mentioned reasonable range, the passivation performance of the aluminum oxide film layer 21 can be ensured, and meanwhile, the problem that the passivation effect is affected due to uneven deposition caused by too thin thickness of the aluminum oxide film layer 21 can be avoided, and the subsequent grooving process is affected due to too thick thickness and the cost is increased can be avoided.

Specifically, in such embodiments, the thickness of the aluminum oxide film layer 21 may be, for example, any value between 8nm, 8.5nm, 9nm, 9.5nm, 10nm, 10.5nm, 11nm, 11.5nm, 12nm, or 8nm-12nm, and is not particularly limited herein.

Example IV

In some embodiments, the thickness of the silicon oxide film layer 22 may be 4nm-10nm.

Thus, by setting the thickness of the silicon oxide film 22 within the above-mentioned reasonable range, the passivation performance of the silicon oxide film 22 can be ensured, and at the same time, the effect of passivation can be prevented from being affected by uneven deposition caused by too thin thickness of the silicon oxide film 22, and the subsequent grooving process and cost increase can be prevented from being affected by too thick thickness.

Specifically, in such embodiments, the thickness of the silicon oxide film layer 22 may be, for example, any number between 4nm, 4.5nm, 5nm, 5.5nm, 6nm, 6.5nm, 7nm, 7.5nm, 8nm, 8.5nm, 9nm, 9.5nm, 10nm, or 4nm-10nm, particularly without limitation herein.

Example five

Referring to fig. 6, in some embodiments, the silicon nitride film 23 may be a composite film, and the silicon nitride film 23 includes at least two silicon nitride films arranged along the front surface of the substrate 10 toward the back surface of the substrate 10 and having sequentially reduced refractive indexes.

In this way, the silicon nitride film layer 23 is configured to include at least two layers of silicon nitride films with sequentially reduced refractive indexes, so that the reflectivity of the back surface film layer structure 20 to the light incident from the front surface of the solar cell 100 can be improved, and more light incident from the front surface and penetrating the substrate 10 is reflected back into the substrate 10, so as to realize light re-absorption and utilization, effectively improve the re-utilization rate of the incident light, and further improve the conversion efficiency of the solar cell 100.

Further, as shown in fig. 6, in some embodiments, the silicon nitride film layer 23 includes a top silicon nitride film 231 stacked on the silicon oxide film layer 22 and a bottom silicon nitride film 232 stacked on the top silicon nitride film 231, the refractive index of the top silicon nitride film 231 may be 2.13-2.15, and the refractive index of the bottom silicon nitride film 232 may be 2.10-2.13.

In this way, by providing the silicon nitride film layer 23 as a two-layer film structure and restricting the refractive index of the two-layer film to the aforementioned range, the reflectivity of the back surface film layer structure 20 to the light incident from the front surface of the solar cell 100 can be improved, thereby improving the conversion efficiency of the solar cell 100.

Further, in such an embodiment, the top silicon nitride film 231 may have a thickness of 20nm-26nm. Thus, by setting the thickness of the top silicon nitride film 231 within the above-mentioned reasonable range, the excessive thickness of the film layer can be avoided to affect the grooving process while ensuring the passivation effect, and the cost increase caused by the excessive thickness can be avoided.

Specifically, in such embodiments, the thickness of the top silicon nitride film 231 may be, for example, any number between 20nm, 20.5nm, 21nm, 21.5nm, 22nm, 22.5nm, 23nm, 23.5nm, 24nm, 24.5nm, 25nm, 25.5nm, 26nm, or 20nm-26nm, without limitation herein.

Further, in some embodiments, the underlying silicon nitride film 232 has a thickness of 22nm-28nm. Thus, by setting the thickness of the underlying silicon nitride film 232 within the above-mentioned reasonable range, the effect of passivation can be ensured while avoiding the influence of excessive thickness of the film layer on the grooving process, and the cost increase caused by excessive thickness can be avoided.

Specifically, in such embodiments, the thickness of the underlying silicon nitride film 232 may be, for example, 22nm, 22.5nm, 23nm, 23.5nm, 24nm, 24.5nm, 25nm, 25.5nm, 26nm, 26.5nm, 27nm, 27.5nm, 28nm, or any value between 22nm-28nm, as particularly not limited herein.

Of course, it is understood that in other embodiments, the silicon nitride film 23 may be a three-layer film structure, a four-layer film structure or even be composed of more silicon nitride films, so long as the refractive index thereof is reduced in order according to the above-mentioned rule, and the utility model is not limited thereto.

In the embodiment of the present utility model, the back surface film layer structure 20 of the solar cell 100 may be formed by deposition using a deposition apparatus such as PECVD, for example, the silicon nitride film layer 23 is a two-layer film structure, which may be specifically manufactured by the following steps:

step 1: the aluminum oxide film layer 21 is deposited on the back of the substrate 10 (the substrate 10 can be obtained by cleaning, texturing, diffusing and the like of a silicon wafer), trimethyl aluminum is introduced in the deposition process, the flow opening of the trimethyl aluminum can be 81, the deposition temperature can be 300-500 ℃, the deposition pressure can be 1000mTorr-1600mTorr, the deposition power can be 3000W-8000W, the deposition time can be 50s-150s, and the duty ratio of the deposition equipment can be 5:120ms-5:200ms, and then forming an alumina film layer 21 with proper thickness;

step 2: depositing a silicon oxide film layer 22 on the aluminum oxide film layer 21, wherein in the deposition process, laughing gas and silane are introduced, the flow rate of the laughing gas can be 5000sccm-14000sccm, the flow rate of the silane can be 500sccm-2300sccm, the deposition temperature can be 320-580 ℃, the deposition pressure can be 800mTorr-2000mTorr, the deposition power can be 6000W-18000W, the deposition time can be 30s-300s, and the duty ratio of the deposition equipment can be 5:40ms-5:200ms, and then forming a silicon oxide film layer 22 with proper thickness;

step 3: depositing a top silicon nitride film 231 on the silicon oxide film layer 22, wherein in the deposition process, ammonia and silane are introduced, the flow rate of the ammonia can be 2000sccm-15000sccm, the flow rate of the silane can be 300sccm-5000sccm, the deposition temperature can be 350-600 ℃, the deposition pressure can be 500mTorr-2000mTorr, the deposition power can be 7000W-16000W, the deposition time can be 50s-300s, and the duty ratio of the deposition equipment can be 5:40ms-5:120ms, and then forming a top silicon nitride film 231 with a proper thickness;

step 4: depositing a bottom silicon nitride film 232 on a top silicon nitride film 231, and introducing ammonia and silane in the deposition process, wherein the flow rate of the ammonia can be 5000sccm-21000sccm, the flow rate of the silane can be 400sccm-2800sccm, the deposition temperature can be 400 ℃ -600 ℃, the deposition pressure can be 700mTorr-9000mTorr, the deposition power can be 8000W-18000W, the deposition time can be 100s-350s, and the duty ratio of the deposition equipment can be 5:50ms-5:140ms, thereby forming a bottom silicon nitride film 232 of suitable thickness;

step 5, depositing a carbon nitride film 24 on the bottom silicon nitride film 232, wherein in the deposition process, ammonia and methane are introduced, the flow rate of the ammonia can be 7000sccm-21000sccm, the flow rate of the methane can be 500sccm-8000sccm, the deposition temperature can be 450-600 ℃, the deposition pressure can be 1000mTorr-9000mTorr, the deposition power can be 8000W-16000W, the deposition time can be 30s-250s, and the duty ratio of the deposition equipment can be 5:50ms-5:120ms, thereby forming a carbon nitride film 24 with a proper thickness;

it should be understood that the above only illustrates the fabrication process of the back surface film layer structure 20, and the front surface film layer structure 30 may be deposited on the front surface of the substrate 10 by PECVD during fabrication, and the deposition sequence of the front surface film layer structure 30 and the back surface film layer structure 20 is not limited. After the front and back side films are deposited, laser grooving may be performed on the front and back side film structures 30 and 20 by laser, and then the front and back side electrodes 50 and 40 may be printed and sintered in the grooved areas.

After the back surface film layer structure 20 in the embodiment of the present utility model is adopted, the inventors of the present utility model respectively compare the electrical properties of the battery sheet in the prior art for producing 2500pcs with the battery sheet in the present utility model, and found that the electrical properties of the solar battery sheet 100 adopting the back surface film layer structure 20 in the embodiment of the present utility model have an efficiency improvement of 0.02% -0.035%, and when the carbon nitride film layer 24 is introduced, the PID data of the solar battery sheet 100 can be reduced from 2.9% to 0.6%. Therefore, by adopting the technical scheme of the utility model, the PID resistance of the solar cell 100 can be improved, and the efficiency of the solar cell 100 can be further improved.

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

Claims (10)

1. The solar cell is characterized by comprising a substrate and a back film layer structure which is arranged on the back of the substrate in a laminated mode, wherein the back film layer structure comprises an aluminum oxide film layer, a silicon nitride film layer and a carbon nitride film layer which are arranged on the back of the substrate in a laminated mode in sequence.

2. The solar cell according to claim 1, wherein the thickness of the carbon nitride film layer is 13nm-20nm.

3. The solar cell according to claim 1, wherein the thickness of the aluminum oxide film layer is 8nm-12nm.

4. The solar cell according to claim 1, wherein the thickness of the silicon oxide film layer is 4nm to 10nm.

5. The solar cell according to claim 1, wherein the silicon nitride film layer is a composite film layer, the silicon nitride film layer including at least two silicon nitride films arranged in a direction from a front surface of the substrate toward a back surface of the substrate and having refractive indexes sequentially reduced.

6. The solar cell according to claim 5, wherein the silicon nitride film layer includes a top silicon nitride film stacked on the silicon oxide film layer and a bottom silicon nitride film stacked on the top silicon nitride film, the top silicon nitride film having a refractive index of 2.13 to 2.15, and the bottom silicon nitride film having a refractive index of 2.10 to 2.13.

7. The solar cell according to claim 6, wherein the top silicon nitride film has a thickness of 20nm-26nm.

8. The solar cell of claim 6, wherein the underlying silicon nitride film has a thickness of 22nm-28nm.

9. A battery assembly comprising a plurality of solar cells according to any one of claims 1-8.

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