A cadmium telluride thin film solar cell, a manufacturing method and a coating device

Abstract

This invention provides a cadmium telluride thin-film solar cell, a manufacturing method, and a coating apparatus. The coating apparatus includes a coating chamber, a feeding assembly, and a storage assembly, a heating assembly, and a transport assembly located within the coating chamber. The storage assembly stores a material source and includes at least one crucible with an opening on its bottom surface. At least a portion of the feeding assembly is located within the coating chamber, with its portion extending into the crucible to replenish the material source. The heating assembly heats the crucible to sublimate and decompose the material source into material source vapor. The transport assembly is located below the storage assembly and supports the substrate, moving it so that the material source vapor is deposited onto the substrate from top to bottom through the opening to form a thin film. This coating apparatus enables top-down diffusion deposition of material source vapor, effectively increasing the power generation area and production efficiency of the cadmium telluride thin-film solar cell. It also enables continuous online feeding, further improving production capacity.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic thin-film batteries, and relates to a cadmium telluride thin-film solar cell, its manufacturing method, and its coating apparatus. Background Technology

[0002] Cadmium telluride (CdTe) thin-film solar cells are among the most commercially successful thin-film solar cells to date. With a band gap of approximately 1.5 eV, they better match the solar spectrum, achieving a theoretical efficiency of 32%, higher than crystalline silicon, and possessing significant cost reduction potential. Currently, the laboratory efficiency of CdTe thin-film solar cells has reached 22.1%, and commercial modules have achieved 19.0%, with costs comparable to crystalline silicon products. Based on this, CdTe cells are the most promising new energy technology for the next few years, with production capacity expected to continue expanding. In the global photovoltaic market, thin-film photovoltaic cells account for approximately 5%, and 80% of thin-film photovoltaic cells are based on CdTe technology.

[0003] CdTe cells are thin-film solar cells based on a heterojunction of p-type CdTe and n-type CdS. Currently, the CdTe absorber layer in most cadmium telluride (CdTe) cells is deposited using a bottom-up near-space sublimation (CSS) process. The advantages of this method are that there is no carrier gas during deposition, which does not affect the deposition process; and no CdTe particles fall into the film during deposition, affecting the film quality. However, please refer to... Figure 1 The diagram shows a simplified structural schematic of a typical near-space sublimation coating apparatus. This method has several significant drawbacks. For example, because the substrate 102 is transported above the material source 103 using rollers 101 to support it, the limited contact area between the substrate 101 and the rollers 101 restricts the transport speed of the substrate 101, affecting production efficiency. Furthermore, roller marks are inevitably left on the coating surface 102a of the substrate 101, which not only affects the appearance but also reduces the effective area of ​​the battery, thus impacting its performance. In addition, the near-space sublimation method requires a single feeding, necessitating a shutdown for refueling every 10-14 days, making it difficult to exceed 80% equipment uptime and further limiting production capacity.

[0004] Therefore, how to provide a cadmium telluride thin-film solar cell, its manufacturing method, and its coating apparatus to improve production capacity while ensuring the cell's performance has become an important technical problem that needs to be solved by those skilled in the art.

[0005] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a cadmium telluride thin-film solar cell, a manufacturing method and a coating apparatus, to solve the problems in the prior art where the near-space sublimation method for manufacturing CdTe absorber layers affects the effective area and transmission speed of the coating surface, and the one-time feeding method prevents the production capacity from being increased.

[0007] To achieve the above and other related objectives, the present invention provides a cadmium telluride thin-film solar cell coating apparatus, comprising:

[0008] Coating cavity;

[0009] A material storage assembly, located within the coating cavity, is provided to store a material source. The material storage assembly includes at least one crucible, the bottom surface of which has an opening.

[0010] A feeding assembly, at least a portion of which is located within the coating cavity, and the portion of the feeding assembly located within the coating cavity extends into the crucible to replenish the material source;

[0011] A heating component is located inside the coating cavity. The heating component is used to heat the crucible so that the material source is heated and sublimated into material source vapor.

[0012] A transfer component is located within the coating cavity and below the material storage component. The transfer component is used to carry the substrate and move the substrate so that the material source vapor is deposited on the substrate from top to bottom through the opening to form a thin film.

[0013] Optionally, the heating assembly includes multiple infrared heaters, which are evenly distributed within the coating cavity.

[0014] Optionally, the infrared heater may be located on at least one of the inner wall of the coating cavity and the outer wall of the crucible.

[0015] Optionally, the feeding assembly includes a continuous feeding device and at least one feeding pipe. The continuous feeding device is located outside the coating chamber, one end of the feeding pipe is connected to the continuous feeding device, and the other end of the feeding pipe extends into the crucible.

[0016] Optionally, the portion of the feeding pipe located between the coating chamber and the continuous feeding device is equipped with multi-stage valves.

[0017] Optionally, the coating apparatus further includes a vacuum pumping component, at least a portion of which is connected to the coating chamber to maintain a preset vacuum level in the coating chamber during coating.

[0018] Optionally, the crucible further includes a baffle that surrounds the opening and extends upward from the bottom wall of the crucible, with the baffle spaced a predetermined distance from the top surface of the crucible.

[0019] Optionally, the material storage assembly further includes a first adjusting plate and a second adjusting plate symmetrically arranged, the first adjusting plate and the second adjusting plate being movably connected to the crucible, and one end of the first adjusting plate and one end of the second adjusting plate extending from inside the crucible through the opening to outside the crucible.

[0020] Optionally, the material source includes at least one of cadmium telluride and cadmium sulfide.

[0021] Optionally, the storage assembly includes a first crucible and a second crucible, the first crucible having a first opening for storing cadmium sulfide, and the second crucible having a second opening for storing cadmium telluride. The transfer assembly carries the substrate and passes it sequentially under the first crucible and under the second crucible to deposit a cadmium sulfide film and a cadmium telluride film sequentially on the substrate based on the first opening and the second opening.

[0022] This invention also provides a method for fabricating a cadmium telluride thin-film solar cell, comprising the following steps:

[0023] A substrate is provided on which a transparent conductive layer is formed;

[0024] A window layer is deposited on the transparent conductive layer;

[0025] An absorption layer is deposited on the window layer, the absorption layer comprising a cadmium telluride thin film, and the deposition of the cadmium telluride thin film is performed in the cadmium telluride thin film solar cell coating apparatus described above.

[0026] A back contact layer and a back electrode layer are sequentially formed on the absorption layer.

[0027] Optionally, the window layer includes a cadmium sulfide thin film, which is deposited in a cadmium telluride thin-film solar cell coating apparatus as described above.

[0028] Optionally, during the deposition of the cadmium sulfide film and the deposition of the cadmium telluride film, the vacuum degree of the coating chamber is less than or equal to 1 mbar.

[0029] The present invention also provides a cadmium telluride thin-film solar cell, which is fabricated using the cadmium telluride thin-film solar cell fabrication method described above.

[0030] As described above, the cadmium telluride thin-film solar cell coating apparatus of the present invention enables top-down diffusion deposition of material source vapor, overcoming the limitations of traditional bottom-up coating processes on coating area and transmission speed. This effectively increases the power generation area and production efficiency of cadmium telluride thin-film solar cells, while also enabling continuous online feeding, thus effectively increasing production line capacity. Furthermore, when the material storage component within the coating apparatus is equipped with a first adjustment plate and a second adjustment plate, the flow rate of sublimated material source vapor in the crucible can be controlled by adjusting the tilt angle of the two adjustment plates, thereby controlling the thickness of the deposited film layer. This allows for the production of film layers of different product models (with varying thicknesses), enabling diversified applications of the coating apparatus. The manufacturing method of the cadmium telluride thin-film solar cell of the present invention ensures the quality of the absorber layer in the cadmium telluride thin-film solar cell and improves manufacturing efficiency. Compared to conventional cadmium telluride thin-film solar cells of the same size, the cadmium telluride thin-film solar cell of the present invention has an increased effective power generation area, thereby improving its performance. Attached Figure Description

[0031] Figure 1 The diagram shows a simplified structural schematic of a typical near-space sublimation coating apparatus.

[0032] Figure 2 This diagram shows a partial cross-sectional view of the cadmium telluride thin-film solar cell coating apparatus of the present invention.

[0033] Figure 3 This diagram shows a partial structural schematic of the cadmium telluride thin-film solar cell coating apparatus of the present invention, with the baffle disposed on the bottom surface of the crucible.

[0034] Figure 4 Displayed as Figure 3 A top-view structural diagram.

[0035] Figure 5 The diagram shows a partial cross-sectional view of the crucible in the cadmium telluride thin-film solar cell coating apparatus of the present invention, when the crucible is equipped with a conical cylindrical baffle.

[0036] Figure 6 The diagram shows a partial cross-sectional view of the cadmium telluride thin-film solar cell coating apparatus of the present invention, with a first crucible and a second crucible.

[0037] Figure 7 The diagram shows a partial cross-sectional view of the material storage assembly in the cadmium telluride thin-film solar cell coating device of the present invention, when the first adjustment plate and the second adjustment plate are provided.

[0038] Figure 8 The diagram shows a partial cross-sectional view of the material storage component in the cadmium telluride thin-film solar cell coating apparatus of the present invention, with baffles and adjustment plates provided.

[0039] Figure 9 The diagram shows the steps of the method for fabricating the cadmium telluride thin-film solar cell of the present invention.

[0040] Figure 10 The diagram shows a cross-sectional structure of a solar cell fabricated using the cadmium telluride thin-film solar cell fabrication method of the present invention.

[0041] Component designation explanation

[0042] 101 rollers

[0043] 102 base

[0044] 102a Coated Surface

[0045] 103 Material Source

[0046] 10 Coating cavity

[0047] 20. Material storage components

[0048] 21. Crucible

[0049] 211 Opening

[0050] 21a First Crucible

[0051] 211a First opening

[0052] 21b Second Crucible

[0053] 211b Second opening

[0054] 212 baffle

[0055] 22a First Adjustment Plate

[0056] 22b Second Adjustment Plate

[0057] 31 Feeding pipe

[0058] 41 Infrared heater

[0059] 51 Rollers

[0060] 60 substrates

[0061] 601 substrate

[0062] 602 transparent conductive layer

[0063] 603 Window Layer

[0064] 604 Absorbing Layer

[0065] 605 Back Contact Layer

[0066] 606 Back Electrode Layer Detailed Implementation

[0067] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0068] Please see Figures 2 to 10 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0069] Example 1

[0070] This embodiment provides a cadmium telluride thin-film solar cell coating apparatus. Please refer to [link / reference]. Figure 2 The diagram shows a partial cross-sectional view of the coating apparatus, specifically including a coating chamber 10, a material storage assembly, a feeding assembly, a heating assembly, and a transfer assembly (all of the above components except the coating chamber 10 are not shown in the diagram). Figure 2 (Chinese logo).

[0071] Specifically, the material storage assembly is located within the coating cavity 10 to store the material source. The material storage assembly includes at least one crucible 21 (including graphite material), and the bottom surface of the crucible 21 has an opening 211. At least a portion of the feeding assembly is located within the coating cavity 10, and the portion of the feeding assembly located within the coating cavity 10 extends into the crucible 21 to replenish the material source. The heating assembly is located within the coating cavity 10 and is used to heat the crucible 21 to cause the material source to sublimate and decompose into vapor. The transfer assembly is located within the coating cavity 10 and below the material storage assembly. The transfer assembly is used to carry the substrate 60 and move the substrate 60 so that the vapor is deposited on the substrate 60 from top to bottom through the opening 211 to form a thin film.

[0072] The coating apparatus of this embodiment improves upon the traditional near-space sublimation coating apparatus where rollers transport the substrate above the material source. Instead, it uses a transport component to transport the substrate below the crucible, with an opening at the bottom of the crucible allowing the sublimated material source vapor to diffuse downwards onto the substrate for deposition and thin film formation. In this configuration, the non-coated surface of the substrate is in direct contact with the transport component, while the coated surface is fully exposed. This avoids the reduction in effective coating area caused by contact between the coated surface and the transport component, thereby improving the overall performance of the solar cell. Furthermore, this support method allows for increasing the contact area between the substrate and the transport component as needed without compromising substrate transport stability due to increased transport speed, thus effectively improving production efficiency. Additionally, the inclusion of a feeding component within the coating apparatus enables online feeding of the material source during the coating process, preventing downtime for feeding and reducing equipment uptime, further increasing production capacity.

[0073] As an example, the material source includes at least one of cadmium telluride and cadmium sulfide. That is, the coating device of this embodiment can deposit cadmium telluride film or cadmium sulfide film. The types of material sources stored in the crucible 21 can be adjusted according to actual needs to achieve diversified use of the device and improve equipment utilization.

[0074] As an example, the feeding assembly includes a continuous feeding device ( Figure 2 (Not shown in the image) and at least one feeding pipe 31, the continuous feeding device is located outside the coating chamber 10, one end of the feeding pipe 31 is connected to the continuous feeding device, and the other end of the feeding pipe 31 extends into the crucible 21. The continuous feeding device is used to transport the material source in the material source storage device to the feeding pipe 31, and then the heating pipe replenishes the crucible 21. During the coating process, the raw material can be replenished without stopping the machine, effectively solving the problem of limited production capacity caused by stopping the machine to feed during the traditional near-space sublimation coating method, and achieving a significant increase in production capacity.

[0075] As an example, the portion of the feeding pipe 31 located between the coating chamber 10 and the continuous feeding device is equipped with multi-stage valves. Figure 2 (Not shown in the text), the multi-stage valve is used to achieve flexible online continuous feeding of material sources.

[0076] As an example, the heating assembly includes multiple infrared heaters 41, which are uniformly distributed within the coating cavity 10. The infrared heaters 41 provide heat to the material source within the crucible 21, causing the material source to sublimate and decompose into vapor. For example, if the material source is cadmium telluride, when the crucible 21 is heated to above 650°C, the CdTe source sublimates and decomposes into Cd and Te2. The infrared heaters 41 also provide heat (radiative heating) to the substrate 60, enabling it to reach a preset temperature (≥500°C), which is beneficial for the uniformity and quality of the deposited film. It should be noted that "uniform distribution" here refers to the arrangement of the multiple infrared heaters 41 ensuring temperature uniformity at various locations within the crucible 21 and at various locations on the substrate 60 as it passes beneath the crucible 21.

[0077] Furthermore, the infrared heater 41 is located in at least one of the inner wall of the coating cavity 10 and the outer wall of the crucible 21. Based on the foregoing, the infrared heater 41, in addition to providing heat to the material source within the crucible 21, also needs to heat the substrate 60. Therefore, the specific location of the infrared heater 41 is set based on actual needs. However, it should be noted that the temperature inside the crucible 21 needs to reach a certain temperature (e.g., 650°C) or higher to allow the material source to sublimate. Therefore, multiple infrared heaters 41 are preferably located close to the crucible 21 (not necessarily directly on the outer wall of the crucible 21) and evenly distributed to ensure uniform heating of all parts of the crucible 21 and the substrate 60 and to achieve precise temperature control.

[0078] As an example, the transmission assembly includes a plurality of spaced rollers 51, and the substrate 60 is placed on the rollers 51 and moves with and as the rollers 51 rotate.

[0079] As an example, the coating apparatus also includes a vacuum assembly ( Figure 2 (Not shown in the text) At least a portion of the vacuum assembly is connected to the coating chamber 10 so that the coating chamber 10 maintains a preset vacuum level during coating. Maintaining the preset vacuum level can improve coating uniformity and coating efficiency.

[0080] As an example, the crucible 21 further includes a baffle 212, which surrounds the opening 211 and extends upward from the bottom wall of the crucible 21, with the baffle 212 spaced from the top surface of the crucible 21 by a predetermined distance. Figure 2(As shown in Figure d). The function of the baffle 212 is to prevent material from the bottom of the crucible 21 from falling onto the substrate 60 or the transfer assembly through the opening 211, thus affecting the coating quality of the substrate 60 and the transfer performance of the transfer assembly. The predetermined distance between the baffle 212 and the top surface of the crucible 21 is to allow the sublimated material vapor in the crucible 21 to diffuse rapidly towards the opening 211 through the gap, avoiding the impact of a small gap on the vapor diffusion rate and thus production efficiency. The specific value is based on a comprehensive consideration of parameters such as the size of the opening 211, the distance between the coating surface of the substrate 60 and the crucible 21, and the transfer speed of the transfer assembly. For a detailed understanding of the structure of the baffle 212 and the positional relationship between the baffle 212 and the opening 211, please refer to [reference needed]. Figure 3 and Figure 4 ,in Figure 3 The diagram shows a partial structural schematic of the baffle 212 being disposed on the bottom surface of the crucible 21. Figure 4 Displayed as Figure 3 A top view of the structure.

[0081] Furthermore, the baffle 212 can be in the shape of a vertical cylinder (e.g., Figure 2 (as shown) the type with the same width at the top and bottom) or the conical cylindrical shape (such as... Figure 5 As shown in the figure, the baffle 212 is wider at the top and narrower at the bottom. The specific shape of the baffle 212 is set according to actual needs. It is preferably a conical cylinder shape, which can maintain good gas flow and allow steam to diffuse downward quickly and evenly from the opening 211.

[0082] In other embodiments, please refer to Figure 6 The diagram shows a partial cross-sectional view of the coating apparatus with a first crucible and a second crucible. The storage assembly includes a first crucible 21a and a second crucible 21b. The first crucible 21a has a first opening 211a for storing cadmium sulfide, and the second crucible 21b has a second opening 211b for storing cadmium telluride. The transfer assembly carries the substrate 60 and passes under the first crucible 21a and the second crucible 21b in sequence to deposit a cadmium sulfide film and a cadmium telluride film on the substrate 60 based on the first opening 211a and the second opening 211b. The first crucible 21a and the second crucible 21b are simultaneously placed in the coating chamber 10 of the coating device. The substrate 60 is then driven by the transmission component to pass under the first crucible 21a and the second crucible 21b in sequence. This allows the substrate 60 to first deposit a cadmium sulfide film and then a cadmium telluride film in one coating device, thus completing the fabrication of the two main film layers of the solar cell. Furthermore, the steps of taking out and putting in the substrate are reduced during the fabrication process, shortening the process cycle and effectively increasing production capacity.

[0083] As an example, the coating apparatus also includes a material source capacity detection component (such as an image sensor, pressure sensor, etc., not shown in the figure) in the crucible 21. The remaining amount of material source in the crucible 21 is detected in real time by the material source capacity detection component so as to replenish the material source in a timely manner and avoid affecting the steam output of the material source due to insufficient material source, thereby affecting the stability of the film thickness.

[0084] The cadmium telluride thin-film solar cell coating apparatus of this embodiment enables top-down diffusion deposition of material source vapor, overcoming the limitations of traditional bottom-up coating processes on coating area and transmission speed. This effectively increases the power generation area and production efficiency of cadmium telluride thin-film solar cells, while also enabling continuous online feeding, thus effectively improving production line capacity. Furthermore, the absence of external gas interference within the coating apparatus ensures thorough mixing of the evaporation source gases, resulting in better coating uniformity.

[0085] Example 2

[0086] This embodiment provides a cadmium telluride thin-film solar cell coating apparatus. The difference between this apparatus and the one in the previous embodiment is that the gas flow rate of the material source vapor is adjustable during coating. Please refer to [link to previous embodiment]. Figure 2 The diagram shows the structure of the coating apparatus, which specifically includes a coating chamber 10, a material storage assembly, a feeding assembly, a heating assembly, and a transfer assembly (all of the above components except the coating chamber 10 are not included in the main structure). Figure 2 (Chinese logo).

[0087] Specifically, the material storage assembly is located within the coating cavity 10 to store the material source. The material storage assembly includes at least one crucible 21, and the bottom surface of the crucible 21 has an opening 211. At least a portion of the feeding assembly is located within the coating cavity 10, and the portion of the feeding assembly located within the coating cavity 10 extends into the crucible 21 to replenish the material source. The heating assembly is located within the coating cavity 10 and is used to heat the crucible 21 to cause the material source to sublimate and decompose into vapor. The transfer assembly is located within the coating cavity 10 and below the material storage assembly. The transfer assembly is used to carry the substrate 60 and move the substrate 60 so that the vapor is deposited on the substrate 60 from top to bottom through the opening 211 to form a thin film.

[0088] For example, please refer to Figure 7The diagram shows a cross-sectional view of the storage assembly with a first adjusting plate and a second adjusting plate. The storage assembly also includes a symmetrically arranged first adjusting plate 22a and a second adjusting plate 22b. The first adjusting plate 22a and the second adjusting plate 22b are movably connected to the crucible 21. One end of the first adjusting plate 22a and one end of the second adjusting plate 22b extend from inside the crucible 21 through the opening 211 to the outside of the crucible 21. The purpose of setting the first adjusting plate 22a and the second adjusting plate 22b is to achieve uniform steam diffusion while flexibly adjusting the output of the material source steam by adjusting the tilt angle of the two adjusting plates (which can be adjusted mechanically). Figure 7 As shown in the diagram (related to w), a thin film with uniform thickness and suitable grain size can be obtained, while also meeting the needs of producing film layers of different thicknesses, realizing diversified applications of the coating device. It should be noted that when flexibly connecting the first adjusting plate 22a and the second adjusting plate 22b to the crucible 21, it is necessary to ensure that the material source at the bottom of the crucible 21 does not fall from the connection point and affect the film quality.

[0089] As an example, the crucible 21 further includes a baffle 212, which surrounds the opening 211 and extends upward from the bottom wall of the crucible 21, with the baffle 212 spaced a predetermined distance from the top surface of the crucible 21. See also... Figure 8 The diagram shows a cross-sectional view of the material storage assembly when it includes both a baffle and an adjusting plate (including a first adjusting plate and a second adjusting plate). With the baffle 212 provided, the first adjusting plate 22a and the second adjusting plate 22b can be movably connected to the crucible 21 through the baffle 212.

[0090] The coating apparatus of this embodiment adds a first adjustment plate and a second adjustment plate to the coating apparatus described in Embodiment 1. By adjusting the tilt angle of the two adjustment plates, the flow rate of the sublimated material source vapor in the crucible can be controlled, thereby controlling the thickness of the deposited film. This enables the production of films of different product models (with varying thicknesses), realizing the diversified application of the coating apparatus.

[0091] Example 3

[0092] This embodiment provides a method for fabricating a cadmium telluride thin-film solar cell, based on the coating apparatus described in any one of Embodiments 1 and 2, or other suitable apparatus. Please refer to [link / reference needed]. Figure 9 The flowchart shown illustrates the steps of this manufacturing method, which specifically includes the following steps:

[0093] S1: A substrate is provided on which a transparent conductive layer is formed;

[0094] S2: Deposit a window layer on the transparent conductive layer;

[0095] S3: An absorption layer is deposited on the window layer, the absorption layer comprising a cadmium telluride thin film, and the deposition of the cadmium telluride thin film is performed in the cadmium telluride thin film solar cell coating apparatus as described above (Example 1 or Example 2).

[0096] S4: A back contact layer and a back electrode layer are sequentially formed on the absorption layer.

[0097] For details, please refer to Figure 10 The diagram shows a cross-sectional structure of a solar cell fabricated using this method. Steps S1 to S5 are executed sequentially, including providing a substrate 601, and depositing a transparent conductive layer 602, a window layer 603, an absorber layer 604, a back contact layer 605, and a back electrode layer 606 on the substrate 601. The absorber layer 604 is deposited using the coating apparatus described in Example 1 or Example 2. The substrate 601 with the window layer 603 deposited then serves as the substrate 60 described in Example 1 and Example 2. The substrate 601 with the window layer 603 deposited is placed on the transport assembly with the window layer 603 facing upwards and then placed in the coating apparatus for coating.

[0098] Specifically, the substrate 601 includes a glass substrate, which mainly serves as a support for the battery, prevents contamination, and allows sunlight to pass through; the transparent conductive layer 602 mainly serves to transmit light and conduct electricity; the window layer 602 (such as a CdS thin film with a band gap of 2.4 eV, allowing most photons to pass through) is an N-type semiconductor and forms a PN junction with the P-type absorption layer 604; the absorption layer 604 (such as a CdTe thin film with a band gap of 1.45 eV) is a P-type semiconductor and serves as the main light-absorbing layer of the solar cell, forming a PN junction with the N-type window layer 602 (the most core functional part of the entire battery); the back contact layer 605 can reduce the contact barrier between the CdTe thin film and the back electrode layer 606 (metal electrode), draw out current, and form an ohmic contact between the metal electrode and the CdTe.

[0099] As an example, the window layer 603 includes a cadmium sulfide thin film, which is deposited in a cadmium telluride thin-film solar cell coating apparatus as described in Example 1 or Example 2. Further, when the coating apparatus includes both a first crucible 21a and a second crucible 21b, a cadmium telluride thin film can be deposited after the cadmium sulfide thin film. When the window layer 603 is also deposited using a coating apparatus, the substrate 601 with the transparent conductive film formed is the substrate 60 described in Examples 1 and 2.

[0100] As an example, during the deposition of the cadmium sulfide thin film and the deposition of the cadmium telluride thin film, the vacuum degree of the coating chamber 10 is less than or equal to 1 mbar. Within the above vacuum degree range, a thin film structure with excellent film quality can be produced.

[0101] The method for fabricating cadmium telluride thin-film solar cells in this embodiment can ensure the quality of the cadmium telluride absorber layer in cadmium telluride thin-film solar cells and improve fabrication efficiency.

[0102] Example 4

[0103] This embodiment provides a cadmium telluride thin-film solar cell, which is fabricated using the cadmium telluride thin-film solar cell fabrication method described in Embodiment 3 above or other suitable methods.

[0104] The cadmium telluride thin-film solar cell of this embodiment has an increased effective power generation area compared to conventional cadmium telluride thin-film solar cells of the same size, thereby improving its performance.

[0105] In summary, the cadmium telluride thin-film solar cell coating apparatus of the present invention enables top-down diffusion deposition of material source vapor, overcoming the limitations of traditional bottom-up coating processes on coating area and transmission speed. This effectively increases the power generation area and production efficiency of cadmium telluride thin-film solar cells, while also enabling continuous online feeding, thus effectively improving production line capacity. Furthermore, when the material storage component within the coating apparatus is equipped with a first and a second adjusting plate, the flow rate of sublimated material source vapor in the crucible can be controlled by adjusting the tilt angle of the two adjusting plates, thereby controlling the thickness of the deposited film layer. This allows for the production of film layers for different product models, enabling diversified applications of the coating apparatus. The manufacturing method of the cadmium telluride thin-film solar cell of the present invention ensures the quality of the absorber layer in the cadmium telluride thin-film solar cell and improves manufacturing efficiency. Compared to conventional cadmium telluride thin-film solar cells of the same size, the cadmium telluride thin-film solar cell of the present invention has an increased effective power generation area, thereby improving its performance. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0106] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A cadmium telluride thin-film solar cell coating apparatus, characterized in that, include: Coating cavity; A material storage assembly, located within the coating cavity, stores the material source. The material storage assembly includes at least one crucible with an opening on its bottom surface. The crucible also includes a baffle plate that surrounds the opening and extends vertically upwards from the bottom wall of the crucible, with a predetermined distance between the baffle plate and the top surface of the crucible. The material storage assembly further includes a symmetrically arranged first adjusting plate and a second adjusting plate, which are movably connected to the crucible via the baffle plate. One end of the first adjusting plate and one end of the second adjusting plate extend from inside the crucible through the opening to the outside of the crucible. The flow rate of the sublimated material source vapor within the crucible is controlled by adjusting the tilt angle of the first adjusting plate and the second adjusting plate, thereby controlling the thickness of the deposited film. A feeding assembly, at least a portion of which is located within the coating cavity, and the portion of the feeding assembly located within the coating cavity extends into the crucible to replenish the material source; A heating assembly is located within the coating cavity. The heating assembly is used to heat the crucible so that the material source is sublimated and decomposed into material source vapor. The heating assembly includes multiple infrared heaters, which are evenly distributed within the coating cavity to provide heat to the material source in the crucible and to the substrate at the same time. A transfer component is located within the coating cavity and below the material storage component. The transfer component is used to carry the substrate and move the substrate so that the material source vapor is deposited on the substrate from top to bottom through the opening to form a thin film.

2. The cadmium telluride thin-film solar cell coating apparatus according to claim 1, characterized in that: The infrared heater is located on at least one of the inner wall of the coating cavity and the outer wall of the crucible.

3. The cadmium telluride thin-film solar cell coating apparatus according to claim 1, characterized in that: The feeding assembly includes a continuous feeding device and at least one feeding pipe. The continuous feeding device is located outside the coating cavity. One end of the feeding pipe is connected to the continuous feeding device, and the other end of the feeding pipe extends into the crucible.

4. The cadmium telluride thin-film solar cell coating apparatus according to claim 3, characterized in that: The portion of the feeding pipe located between the coating chamber and the continuous feeding device is equipped with multi-stage valves.

5. The cadmium telluride thin-film solar cell coating apparatus according to claim 1, characterized in that: The coating apparatus further includes a vacuum pumping component, at least a portion of which is connected to the coating cavity to maintain a preset vacuum level in the coating cavity during coating.

6. The cadmium telluride thin-film solar cell coating apparatus according to claim 1, characterized in that: The material source includes at least one of cadmium telluride and cadmium sulfide.

7. The cadmium telluride thin-film solar cell coating apparatus according to claim 1, characterized in that: The storage assembly includes a first crucible and a second crucible. The first crucible has a first opening for storing cadmium sulfide, and the second crucible has a second opening for storing cadmium telluride. The transfer assembly carries the substrate and passes it sequentially under the first crucible and under the second crucible to deposit a cadmium sulfide film and a cadmium telluride film sequentially on the substrate based on the first opening and the second opening.

8. A method for fabricating a cadmium telluride thin-film solar cell, characterized in that, Includes the following steps: A substrate is provided on which a transparent conductive layer is formed; A window layer is deposited on the transparent conductive layer; An absorption layer is deposited on the window layer, the absorption layer comprising a cadmium telluride thin film, and the deposition of the cadmium telluride thin film is performed in the cadmium telluride thin film solar cell coating apparatus as described in any one of claims 1-7; A back contact layer and a back electrode layer are sequentially formed on the absorption layer.

9. The method for fabricating cadmium telluride thin-film solar cells according to claim 8, characterized in that: The window layer comprises a cadmium sulfide thin film, which is deposited in a cadmium telluride thin-film solar cell coating apparatus as described in any one of claims 1-7.

10. The method for fabricating a cadmium telluride thin-film solar cell according to claim 9, characterized in that: During the deposition of the cadmium sulfide film and the deposition of the cadmium telluride film, the vacuum degree of the coating chamber is less than or equal to 1 mbar.

11. A cadmium telluride thin-film solar cell, characterized in that: The cadmium telluride thin-film solar cell is manufactured using the method described in any one of claims 8-10.

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