Cadmium chloride heat treatment method of cadmium telluride battery and device system thereof

Abstract

The invention belongs to the technical field of battery manufacturing, and relates to a cadmium chloride heat treatment method of a cadmium telluride battery and a device system thereof, and the cadmium chloride heat treatment method comprises the steps of cadmium telluride sample preheating, cadmium chloride thermal spraying and annealing treatment which are carried out in sequence; wherein in the cadmium chloride thermal spraying process, a cadmium chloride solution and a cadmium telluride sample are heated respectively; the cadmium chloride thermal spraying and the annealing treatment are respectively carried out for at least one time. According to the cadmium chloride heat treatment method provided by the invention, the cadmium telluride sample and the cadmium chloride solution are respectively heated before spraying, so that refined and dispersed cadmium chloride particles mainly reach the surface of the cadmium telluride sample, and the continuity and microscopic uniformity of a cadmium chloride film layer are improved; the efficiency of the cadmium telluride thin film assembly is improved, and meanwhile the processing cost and the equipment cost are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of battery manufacturing, and relates to a cadmium telluride battery, and in particular to a cadmium chloride heat treatment method of the cadmium telluride battery and a device system thereof. Background Art

[0002] At present, cadmium telluride thin-film solar cells, as the most successful commercial thin-film solar cell technology, play an important role in energy conservation and emission reduction. The cadmium chloride heat treatment process plays a decisive role in the preparation of high-efficiency cadmium telluride thin-film modules. However, the cadmium telluride absorber layer material that has not been heat treated with cadmium chloride has a large number of defects, which can easily cause serious photogenerated carrier recombination, resulting in poor module efficiency, even less than 10%. In contrast, the defects and recombination of the cadmium telluride absorber layer material that has been heat treated with cadmium chloride are significantly reduced, and the module efficiency can be increased to more than 15%, up to 19%.

[0003] The existing cadmium chloride heat treatment process includes two processes: wet process and dry process. Among them, the wet process usually uses a cadmium chloride solution to apply the solution to the surface of cadmium telluride by spraying, roller coating, immersion, etc., and then annealing at 300-550℃ in the air or protective atmosphere. The dry process uses vacuum coating equipment to deposit a 100-1000nm cadmium chloride film on the surface of the cadmium telluride film, and then annealing at 300-550℃.

[0004] Compared with the wet process, the dry process can produce a more evenly distributed cadmium chloride film layer, which is beneficial to improve the uniformity of the heat treatment of cadmium chloride and improve the efficiency of cadmium telluride thin film modules. However, the dry process has high requirements for vacuum equipment, and the equipment and component manufacturing costs are high. Relatively speaking, the wet process is simple, with low equipment and manufacturing costs, and is more conducive to large-scale industrialization. However, the currently used wet process makes it difficult to obtain a uniformly distributed cadmium chloride film layer, which in turn has an adverse effect on the heat treatment effect of cadmium chloride and the efficiency of cadmium telluride modules.

[0005] In order to further improve the uniformity of wet-process cadmium chloride, technicians in this field mainly made improvements in wet process and chlorine-containing solution formulation, which improved the macroscopic distribution uniformity of cadmium chloride to a certain extent. However, the microscopic distribution uniformity at the micrometer scale did not improve, and there was still a large part of the surface of the cadmium telluride film without cadmium chloride distribution, and it was impossible to achieve uniform coverage of the entire area.

[0006] In addition, the wet process mainly includes spraying and roller coating. Spraying reaches the cadmium telluride film surface in the form of atomized droplets, while roller coating reaches the cadmium telluride film surface in the form of cadmium chloride solution. Both of them will then undergo a process of solution volatilization and cadmium chloride crystallization. During the crystallization process, cadmium chloride is very easy to agglomerate to form dispersed particles, resulting in discontinuity and incomplete coverage of the film layer.

[0007] It can be seen that how to provide a cadmium chloride heat treatment method for cadmium telluride batteries, improve the continuity and microscopic uniformity of the cadmium chloride film layer, and reduce the processing cost and equipment cost while improving the efficiency of cadmium telluride thin film modules has become an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a cadmium chloride heat treatment method for cadmium telluride batteries and a device system thereof, which improves the continuity and microscopic uniformity of the cadmium chloride film layer, thereby improving the efficiency of cadmium telluride thin film modules and reducing processing costs and equipment costs.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a cadmium chloride heat treatment method for a cadmium telluride battery, comprising sequentially performing cadmium telluride sample preheating, cadmium chloride thermal spraying and annealing treatment.

[0011] Wherein, during the cadmium chloride thermal spraying process, the cadmium chloride solution and the cadmium telluride sample are heated respectively; and the cadmium chloride thermal spraying and annealing treatment are performed at least once respectively.

[0012] The cadmium chloride heat treatment method provided by the present invention heats the cadmium telluride sample and the cadmium chloride solution respectively before spraying, so that the atomized cadmium chloride droplets are subjected to high temperature when migrating to the surface of the cadmium telluride sample, and the solvent (such as water or ethanol) is vaporized, and what finally reaches the surface of the cadmium telluride sample are mainly refined and dispersed cadmium chloride particles. Such tiny solid particles are directly adsorbed on the surface of the cadmium telluride film to form a film, thereby avoiding the crystallization and agglomeration effects of the droplets, thereby preventing the formation of dispersed large particles, and the high temperature of the sample is also conducive to the lateral migration of small particles (reaction precursors) in the nucleation process in the initial stage of film formation, which significantly improves the continuity and microscopic uniformity of the cadmium chloride film layer.

[0013] In addition, the present invention heats the cadmium chloride solution, thereby reducing the adverse effect of cadmium chloride spraying on the temperature uniformity of the cadmium telluride sample, thereby effectively preventing the glass substrate of the sample from cracking due to uneven heating, and the subsequent annealing treatment fully reduces the defects and recombination in the cadmium telluride thin film material, improves the efficiency of the cadmium telluride thin film module, and reduces the processing cost and equipment cost, which is conducive to large-scale promotion and application.

[0014] Preferably, the cadmium chloride heat treatment method comprises sequentially performing preheating of the cadmium telluride sample, first cadmium chloride thermal spraying, first annealing treatment, second cadmium chloride thermal spraying and second annealing treatment.

[0015] The present invention adopts secondary chlorine treatment to promote the full diffusion of selenium in the cadmium telluride layer, perform secondary passivation on defects, significantly increase the short-circuit current density, and improve the battery performance and power generation efficiency.

[0016] Preferably, the cadmium telluride sample is first subjected to atmospheric plasma cleaning before being preheated.

[0017] Preferably, a second atmospheric plasma cleaning is performed on the cadmium telluride sample between the preheating of the cadmium telluride sample and the thermal spraying of cadmium chloride.

[0018] Preferably, the preheating temperature of the cadmium telluride sample is 50-200°C.

[0019] Preferably, during the cadmium chloride thermal spraying process, the heating temperature of the cadmium chloride solution is 50-100°C.

[0020] Preferably, during the cadmium chloride thermal spraying process, the heating temperature of the cadmium telluride sample is 50-200°C.

[0021] Preferably, the annealing temperature is 300-450°C.

[0022] Preferably, the cadmium chloride solution concentration used in the cadmium chloride heat treatment method is 5-30wt%, and the spraying flow rate is 2-4mL / min.

[0023] In a second aspect, the present invention provides a device system used in the cadmium chloride heat treatment method as described in the first aspect, comprising a preheating chamber, a thermal spraying chamber and an annealing chamber connected in sequence.

[0024] The preheating chamber, the thermal spraying chamber and the annealing chamber are respectively provided with sample heating devices, and the thermal spraying chamber is also provided with a solution heating device and a spraying device.

[0025] Preferably, the device system comprises a preheating chamber, a first thermal spraying chamber, a first annealing chamber, a second thermal spraying chamber and a second annealing chamber which are connected in sequence.

[0026] Preferably, a first atmospheric plasma cleaning device is provided upstream of the preheating chamber.

[0027] Preferably, a second atmospheric plasma cleaning device is provided between the preheating chamber and the thermal spraying chamber.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The cadmium chloride heat treatment method provided by the present invention heats the cadmium telluride sample and the cadmium chloride solution separately before spraying, so that the atomized cadmium chloride droplets are subjected to high temperature when migrating to the surface of the cadmium telluride sample, and the solvent is vaporized. Finally, what reaches the surface of the cadmium telluride sample are mainly fine and dispersed cadmium chloride particles. Such tiny solid particles are directly adsorbed on the surface of the cadmium telluride film to form a film, avoiding the crystallization and agglomeration effects of the droplets, thereby preventing the formation of dispersed large particles. In addition, the high temperature of the sample is also conducive to the lateral migration of small particles in the nucleation process in the initial stage of film formation, which significantly improves the continuity and microscopic uniformity of the cadmium chloride film layer.

[0030] (2) The present invention heats the cadmium chloride solution, thereby reducing the adverse effect of cadmium chloride spraying on the temperature uniformity of the cadmium telluride sample, thereby effectively preventing the glass substrate of the sample from cracking due to uneven heating. The subsequent annealing treatment fully reduces the defects and recombination in the cadmium telluride thin film material, improves the efficiency of the cadmium telluride thin film module, and reduces the processing cost and equipment cost, which is conducive to large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram of the structure of the device system for heat treatment of cadmium chloride provided in Example 1;

[0032] Figure 2 is a schematic diagram of the structure of the device system for heat treatment of cadmium chloride provided in Example 2;

[0033] Figure 3 This is a schematic diagram of the structure of the device system for heat treatment of cadmium chloride provided in Comparative Example 1;

[0034] Figure 4 The present invention is a schematic structural diagram of a cadmium telluride battery prepared by the cadmium chloride heat treatment method provided by the present invention.

[0035] Among them: 10-preheating chamber; 20-thermal spraying chamber; 21-first thermal spraying chamber; 22-second thermal spraying chamber; 30-annealing chamber; 31-first annealing chamber; 32-second annealing chamber; 40-sample heating device; 50-solution heating device; 60-spraying device; 71-first atmospheric plasma cleaning device; 72-second atmospheric plasma cleaning device; 80-cadmium telluride sample; 90-conveyor belt; 101-glass substrate; 102-transparent conductive oxide layer; 103-window layer; 104-absorption layer; 105-back contact layer; 106-back electrode layer. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0037] A certain embodiment of the present invention provides a cadmium chloride heat treatment method for a cadmium telluride battery, comprising sequentially preheating a cadmium telluride sample, thermal spraying of cadmium chloride, and annealing treatment.

[0038] In which, during the cadmium chloride thermal spraying process, the cadmium chloride solution and the cadmium telluride sample are heated respectively; the cadmium chloride thermal spraying and annealing treatment are performed at least once, for example, once, twice, three times, four times or five times, but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] The cadmium chloride heat treatment method provided by the present invention heats the cadmium telluride sample and the cadmium chloride solution respectively before spraying, so that the atomized cadmium chloride droplets are subjected to high temperature when migrating to the surface of the cadmium telluride sample, and the solvent (such as water or ethanol) is vaporized, and what finally reaches the surface of the cadmium telluride sample are mainly refined and dispersed cadmium chloride particles. Such tiny solid particles are directly adsorbed on the surface of the cadmium telluride film to form a film, thereby avoiding the crystallization and agglomeration effects of the droplets, thereby preventing the formation of dispersed large particles, and the high temperature of the sample is also conducive to the lateral migration of small particles (reaction precursors) in the nucleation process in the initial stage of film formation, which significantly improves the continuity and microscopic uniformity of the cadmium chloride film layer.

[0040] In addition, the present invention heats the cadmium chloride solution, thereby reducing the adverse effect of cadmium chloride spraying on the temperature uniformity of the cadmium telluride sample, thereby effectively preventing the glass substrate of the sample from cracking due to uneven heating, and the subsequent annealing treatment fully reduces the defects and recombination in the cadmium telluride thin film material, improves the efficiency of the cadmium telluride thin film module, and reduces the processing cost and equipment cost, which is conducive to large-scale promotion and application.

[0041] In certain embodiments, the cadmium chloride thermal treatment method includes sequentially performing cadmium telluride sample preheating, first cadmium chloride thermal spraying, first annealing treatment, second cadmium chloride thermal spraying, and second annealing treatment.

[0042] The present invention adopts secondary chlorine treatment to promote the full diffusion of selenium in the cadmium telluride layer, perform secondary passivation on defects, significantly increase the short-circuit current density, and improve the battery performance and power generation efficiency.

[0043] In some embodiments, the cadmium telluride sample is first subjected to an atmospheric plasma cleaning before the cadmium telluride sample is preheated.

[0044] In certain embodiments, a second atmospheric plasma cleaning is performed on the cadmium telluride sample between preheating the cadmium telluride sample and thermal spraying of cadmium chloride.

[0045] The present invention performs plasma surface treatment on a cadmium telluride sample through atmospheric plasma cleaning, thereby achieving surface modification and fully improving the wettability of sprayed cadmium chloride droplets on the surface of a cadmium telluride film.

[0046] In some embodiments, the preheating temperature of the cadmium telluride sample is 50-200°C, for example, it can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] In some embodiments, during the cadmium chloride thermal spraying process, the heating temperature of the cadmium chloride solution is 50-100°C, for example, it can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] In some embodiments, during the cadmium chloride thermal spraying process, the heating temperature of the cadmium telluride sample is 50-200°C, for example, it can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] In some embodiments, the annealing temperature is 300-450°C, for example, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C or 450°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] In certain embodiments, the concentration of the cadmium chloride solution used in the cadmium chloride heat treatment method is 5-30wt%, for example, it can be 5wt%, 6wt%, 8wt%, 10wt%, 12wt%, 14wt%, 16wt%, 18wt%, 20wt%, 22wt%, 24wt%, 26wt%, 28wt% or 30wt%, and the spraying flow rate is 2-4mL / min, for example, it can be 2mL / min, 2.2mL / min, 2.4mL / min, 2.6mL / min, 2.8mL / min, 3mL / min, 3.2mL / min, 3.4mL / min, 3.6mL / min, 3.8mL / min or 4mL / min, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0051] A certain embodiment of the present invention provides a device system used in the above-mentioned cadmium chloride heat treatment method, including a preheating chamber, a thermal spraying chamber and an annealing chamber connected in sequence.

[0052] The preheating chamber, the thermal spraying chamber and the annealing chamber are respectively provided with sample heating devices, and the thermal spraying chamber is also provided with a solution heating device and a spraying device.

[0053] In the present invention, the sample heating device and the solution heating device may be heating wires or heating lamps, etc., respectively, as long as they can achieve the heating function, so the specific structure of each heating device is not particularly limited here.

[0054] In the present invention, the preheating chamber, the thermal spraying chamber and the annealing chamber can be connected in sequence through a high temperature resistant conveying device, as long as the conveying function can be achieved, so the specific structure of the high temperature resistant conveying device is not particularly limited here.

[0055] In some embodiments, the apparatus system includes a preheating chamber, a first thermal spraying chamber, a first annealing chamber, a second thermal spraying chamber, and a second annealing chamber connected in sequence.

[0056] In the present invention, the spraying solution and heating temperature used in the first thermal spraying chamber and the second thermal spraying chamber can be the same or different; the heating temperature and time of the first annealing chamber and the second annealing chamber can be the same or different; they can be adjusted according to experimental needs, thereby further promoting the diffusion of selenium in the selenium-doped multilayer cadmium telluride battery absorption layer.

[0057] Exemplarily, the first thermal spraying chamber uses a 5wt% cadmium chloride solution, and the second thermal spraying chamber uses a 5wt% cadmium chloride solution or a 10wt% cadmium chloride solution; the sample temperature in the first thermal spraying chamber is 100°C, and the sample temperature in the second thermal spraying chamber is 150°C.

[0058] In some embodiments, a first atmospheric plasma cleaning device is disposed upstream of the preheating chamber.

[0059] In some embodiments, a second atmospheric plasma cleaning device is provided between the preheating chamber and the thermal spraying chamber.

[0060] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0061] Example 1

[0062] This embodiment provides a device system for heat treatment of cadmium chloride, such as Figure 1 As shown, the device system includes a preheating chamber 10 , a thermal spraying chamber 20 and an annealing chamber 30 which are sequentially connected by a conveyor belt 90 .

[0063] The preheating chamber 10, the thermal spraying chamber 20 and the annealing chamber 30 are respectively provided with a sample heating device 40, and the thermal spraying chamber 20 is also provided with a solution heating device 50 and a spraying device 60. A first atmospheric plasma cleaning device 71 is provided upstream of the preheating chamber 10, and a second atmospheric plasma cleaning device 72 is provided between the preheating chamber 10 and the thermal spraying chamber 20.

[0064] In this embodiment, the cadmium telluride sample 80 passes through the first atmospheric plasma cleaning device 71 , the preheating chamber 10 , the second atmospheric plasma cleaning device 72 , the thermal spraying chamber 20 and the annealing chamber 30 in sequence by means of the conveyor belt 90 .

[0065] Example 2

[0066] This embodiment provides a device system for heat treatment of cadmium chloride, such as Figure 2 As shown, the device system includes a preheating chamber 10 , a first thermal spraying chamber 21 , a first annealing chamber 31 , a second thermal spraying chamber 22 and a second annealing chamber 32 which are sequentially connected by a conveyor belt 90 .

[0067] The preheating chamber 10, the first thermal spraying chamber 21, the first annealing chamber 31, the second thermal spraying chamber 22 and the second annealing chamber 32 are respectively provided with a sample heating device 40, and the first thermal spraying chamber 21 and the second thermal spraying chamber 22 are also provided with a solution heating device 50 and a spraying device 60. A first atmospheric plasma cleaning device 71 is provided upstream of the preheating chamber 10, and a second atmospheric plasma cleaning device 72 is provided between the preheating chamber 10 and the first thermal spraying chamber 21.

[0068] In this embodiment, the cadmium telluride sample 80 passes through the first atmospheric plasma cleaning device 71, the preheating chamber 10, the second atmospheric plasma cleaning device 72, the first thermal spraying chamber 21, the first annealing chamber 31, the second thermal spraying chamber 22 and the second annealing chamber 32 in sequence by means of the conveyor belt 90.

[0069] Comparative Example 1

[0070] This comparative example provides a device system for heat treatment of cadmium chloride, such as Figure 3 As shown, the device system includes a thermal spraying chamber 20 and an annealing chamber 30 which are sequentially connected by a conveyor belt 90 .

[0071] The thermal spraying chamber 20 is provided with a spraying device 60 , and the annealing chamber 30 is provided with a sample heating device 40 .

[0072] In this comparative example, the cadmium telluride sample 80 passes through the thermal spray chamber 20 and the annealing chamber 30 in sequence by means of a conveyor belt 90 .

[0073] Application Example 1

[0074] This application example uses the device system provided in Example 1 to perform cadmium chloride heat treatment of cadmium telluride batteries, including first atmospheric plasma cleaning, cadmium telluride sample preheating, second atmospheric plasma cleaning, cadmium chloride thermal spraying and annealing treatment in sequence.

[0075] Among them, the preheating temperature of the cadmium telluride sample is 50°C; during the cadmium chloride thermal spraying process, the cadmium chloride solution and the cadmium telluride sample are heated separately, and the heating temperature of the cadmium chloride solution is 50°C, the heating temperature of the cadmium telluride sample is 50°C, the concentration of the cadmium chloride solution is 5wt%, and the spraying flow rate is 2mL / min; the temperature of the annealing treatment is 300°C.

[0076] Application Example 2

[0077] This application example uses the device system provided in Example 1 to perform cadmium chloride heat treatment of cadmium telluride batteries, including first atmospheric plasma cleaning, cadmium telluride sample preheating, second atmospheric plasma cleaning, cadmium chloride thermal spraying and annealing treatment in sequence.

[0078] Among them, the preheating temperature of the cadmium telluride sample is 150°C; during the cadmium chloride thermal spraying process, the cadmium chloride solution and the cadmium telluride sample are heated separately, and the heating temperature of the cadmium chloride solution is 80°C, the heating temperature of the cadmium telluride sample is 150°C, the concentration of the cadmium chloride solution is 20wt%, and the spraying flow rate is 3mL / min; the temperature of the annealing treatment is 350°C.

[0079] Application Example 3

[0080] This application example uses the device system provided in Example 1 to perform cadmium chloride heat treatment of cadmium telluride batteries, including first atmospheric plasma cleaning, cadmium telluride sample preheating, second atmospheric plasma cleaning, cadmium chloride thermal spraying and annealing treatment in sequence.

[0081] Among them, the preheating temperature of the cadmium telluride sample is 200°C; during the cadmium chloride thermal spraying process, the cadmium chloride solution and the cadmium telluride sample are heated separately, and the heating temperature of the cadmium chloride solution is 90°C, the heating temperature of the cadmium telluride sample is 200°C, the concentration of the cadmium chloride solution is 30wt%, and the spraying flow rate is 4mL / min; the temperature of the annealing treatment is 450°C.

[0082] Application Example 4

[0083] This application example uses the device system provided in Example 2 to perform cadmium chloride heat treatment of cadmium telluride batteries, including first atmospheric plasma cleaning, cadmium telluride sample preheating, second atmospheric plasma cleaning, first cadmium chloride thermal spraying, first annealing treatment, second cadmium chloride thermal spraying and second annealing treatment.

[0084] Among them, the preheating temperature of the cadmium telluride sample is 150°C; during the first cadmium chloride thermal spraying and the second cadmium chloride thermal spraying process, the cadmium chloride solution and the cadmium telluride sample are heated respectively, and the heating temperature of the cadmium chloride solution is 80°C, the heating temperature of the cadmium telluride sample is 150°C, the concentration of the cadmium chloride solution is 20wt%, and the spraying flow rate is 3mL / min; the temperature of the first annealing treatment and the second annealing treatment is 350°C.

[0085] Application Example 5

[0086] This application example uses the device system provided in Example 2 to perform cadmium chloride heat treatment of cadmium telluride batteries, including first atmospheric plasma cleaning, cadmium telluride sample preheating, second atmospheric plasma cleaning, first cadmium chloride thermal spraying, first annealing treatment, second cadmium chloride thermal spraying and second annealing treatment.

[0087] Among them, the preheating temperature of the cadmium telluride sample is 150°C; during the first cadmium chloride thermal spraying and the second cadmium chloride thermal spraying, the cadmium chloride solution and the cadmium telluride sample are heated respectively; the heating temperature of the cadmium chloride solution used in the first cadmium chloride thermal spraying is 50°C, the heating temperature of the cadmium telluride sample is 150°C, the concentration of the cadmium chloride solution is 5wt%, and the spraying flow rate is 2mL / min; the heating temperature of the cadmium chloride solution used in the second cadmium chloride thermal spraying is 90°C, the heating temperature of the cadmium telluride sample is 150°C, the concentration of the cadmium chloride solution is 30wt%, and the spraying flow rate is 4mL / min; the temperature of the first annealing treatment is 300°C, and the temperature of the second annealing treatment is 450°C.

[0088] Comparative application example 1

[0089] This comparative application example adopts the device system provided in Comparative Example 1 to perform cadmium chloride heat treatment of cadmium telluride batteries, including sequential cadmium chloride spraying and annealing treatment.

[0090] In the cadmium chloride spraying process, the cadmium telluride sample and the cadmium chloride solution are both at room temperature, the concentration of the cadmium chloride solution is 20wt%, and the spraying flow rate is 3mL / min; the temperature of the annealing treatment is 350°C.

[0091] Performance Testing

[0092] The cadmium telluride batteries were prepared by the cadmium chloride heat treatment methods provided in Application Examples 1-5 and Comparative Application Example 1, respectively. Figure 4 As shown, the cadmium telluride cell includes a stacked glass substrate 101, a transparent conductive oxide layer 102 (SnO2:F), a window layer 103 (CdS), an absorption layer 104 (CdTe:CdSe), a back contact layer 105 (ZnTe:Cu) and a back electrode layer 106 (Mo).

[0093] Specifically, the thickness of the glass substrate 101 is 3.2 mm, the thickness of the transparent conductive oxide layer 102 is 400 nm, the thickness of the window layer 103 is 100 nm, the thickness of the absorption layer 104 is 4 mm, the thickness of the back contact layer 105 is 50 nm, and the thickness of the back electrode layer 106 is 200 nm.

[0094] In addition, the glass substrate 101 is ultra-white float glass, the transparent conductive oxide layer 102 is made by sputtering, the window layer 103 and the absorption layer 104 are both made by close-space sublimation, and the back contact layer 105 and the back electrode layer 106 are both made by sputtering.

[0095] Since the specific preparation process of the above-mentioned layers has no obvious effect on the performance of the final product, the specific steps and parameter conditions of each process are not described here.

[0096] After testing, the cadmium chloride coverage rate on the surface of the cadmium telluride battery, the number of large cadmium chloride particles and the battery efficiency obtained by the cadmium chloride heat treatment method provided in Application Examples 1-5 and Comparative Application Example 1 are shown in Table 1 below.

[0097] Table 1

[0098]

[0099] It can be seen from Table 1 that: in comparative application example 1, there is a droplet aggregation phenomenon when spraying CdCl2 solution at room temperature, which leads to uneven distribution of cadmium chloride and low cadmium chloride coverage; application examples 1-3 can reduce droplet aggregation through thermal spraying and significantly improve cadmium chloride coverage; application examples 4-5 can further improve cadmium chloride distribution through secondary spraying and secondary annealing, and because secondary spraying and secondary annealing can promote Se diffusion, the battery efficiency is further improved.

[0100] It can be seen that the cadmium chloride heat treatment method provided by the present invention heats the cadmium telluride sample and the cadmium chloride solution separately before spraying, so that the atomized cadmium chloride droplets are subjected to high temperature when migrating to the surface of the cadmium telluride sample, and the solvent is vaporized, and what finally reaches the surface of the cadmium telluride sample are mainly refined and dispersed cadmium chloride particles. Such tiny solid particles are directly adsorbed on the surface of the cadmium telluride film to form a film, avoiding the crystallization and agglomeration effects of the droplets, thereby preventing the formation of dispersed large particles, and the high temperature of the sample is also conducive to the lateral migration of small particles in the nucleation process in the initial stage of film formation, which significantly improves the continuity and microscopic uniformity of the cadmium chloride film layer.

[0101] In addition, the present invention heats the cadmium chloride solution, thereby reducing the adverse effect of cadmium chloride spraying on the temperature uniformity of the cadmium telluride sample, thereby effectively preventing the glass substrate of the sample from cracking due to uneven heating, and the subsequent annealing treatment fully reduces the defects and recombination in the cadmium telluride thin film material, improves the efficiency of the cadmium telluride thin film module, and reduces the processing cost and equipment cost, which is conducive to large-scale promotion and application.

[0102] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A cadmium chloride heat treatment method for a cadmium telluride battery, characterized in that: The cadmium chloride heat treatment method comprises sequentially preheating the cadmium telluride sample, thermal spraying of cadmium chloride and annealing treatment; Wherein, during the cadmium chloride thermal spraying process, the cadmium chloride solution and the cadmium telluride sample are heated respectively; and the cadmium chloride thermal spraying and annealing treatment are performed at least once respectively.

2. The cadmium chloride heat treatment method according to claim 1, characterized in that: The cadmium chloride heat treatment method comprises preheating of a cadmium telluride sample, first cadmium chloride thermal spraying, first annealing treatment, second cadmium chloride thermal spraying and second annealing treatment performed in sequence.

3. The cadmium chloride heat treatment method according to claim 1, characterized in that: Before the cadmium telluride sample is preheated, the cadmium telluride sample is first subjected to atmospheric plasma cleaning; And / or, a second atmospheric plasma cleaning is performed on the cadmium telluride sample between the preheating of the cadmium telluride sample and the thermal spraying of cadmium chloride.

4. The cadmium chloride heat treatment method according to claim 1, characterized in that: The cadmium telluride sample is preheated at a temperature of 50-200°C.

5. The cadmium chloride heat treatment method according to claim 1, characterized in that: During the cadmium chloride thermal spraying process, the heating temperature of the cadmium chloride solution is 50-100° C.; And / or, during the cadmium chloride thermal spraying process, the heating temperature of the cadmium telluride sample is 50-200°C.

6. The cadmium chloride heat treatment method according to claim 1, characterized in that: The annealing temperature is 300-450°C.

7. The cadmium chloride heat treatment method according to claim 1 or 2, characterized in that: The cadmium chloride heat treatment method adopts a cadmium chloride solution with a concentration of 5-30wt% and a spraying flow rate of 2-4mL / min.

8. A device system used in the cadmium chloride heat treatment method according to any one of claims 1 to 7, characterized in that: The device system comprises a preheating chamber, a thermal spraying chamber and an annealing chamber connected in sequence; The preheating chamber, the thermal spraying chamber and the annealing chamber are respectively provided with sample heating devices, and the thermal spraying chamber is also provided with a solution heating device and a spraying device.

9. The device system according to claim 8, characterized in that: The device system comprises a preheating chamber, a first thermal spraying chamber, a first annealing chamber, a second thermal spraying chamber and a second annealing chamber which are connected in sequence.

10. The device system according to claim 8, characterized in that: A first atmospheric plasma cleaning device is provided upstream of the preheating chamber; And / or, a second atmospheric plasma cleaning device is provided between the preheating chamber and the thermal spraying chamber.

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