Annealing method and annealing device of solar cell

Abstract

The invention provides an annealing method and an annealing device of a solar cell, which are applied to the solar cell of which the same surface comprises two different sub-regions, and the annealing method comprises the following steps: irradiating a first region and a second region by adopting laser; wherein at least one of the laser parameters for irradiating at least part of the first area and the laser parameters for irradiating at least part of the second area is different, and the laser parameters comprise laser power density and laser irradiation time. According to the method, a selective laser annealing mode is adopted, different laser process parameters are adopted for the two different sub-regions, finally, the two regions form a good passivation effect, and the contact resistance of metal and a silicon layer is improved.

Description

Technical Field

[0001] The present application belongs to the field of photovoltaics, and specifically, relates to an annealing method and an annealing device for a solar cell. Background Art

[0002] At present, various types of solar cells are annealed after metallization. Among them, light injection annealing activates H atoms in the passivation film by increasing the temperature. At the same time, the valence state of the atoms is controlled by light, so that they combine with the recombination center (defect) at the silicon substrate interface to form a non-recombination center, ultimately achieving a good passivation effect.

[0003] In the prior art, TOPCon cells, HJT cells, PERC cells, etc. are mostly annealed using tunnel-type LED light injection annealing furnaces or tunnel-type laser light injection annealing equipment. However, these annealing methods, which use resistance wires or infrared lamps for heating and LED or laser light injection, all heat and inject light into the entire surface of the cell. With the continuous development of photovoltaic technology, solar cells with two different sub-regions on the same surface have emerged. The full-surface annealing method of the prior art cannot make this type of solar cell perform better. Summary of the invention

[0004] In view of this, the present application provides a solar cell annealing method and annealing device.

[0005] According to one aspect of the present invention, there is provided a method for annealing a solar cell, which is applied to a solar cell including two different sub-regions on the same surface, wherein the solar cell includes at least one first region and at least one second region located on the same surface, and the first region is different from the second region, and the method for annealing a solar cell comprises:

[0006] Laser is used to irradiate the first area and the second area; wherein at least one of the laser parameters for irradiating at least a portion of the first area is different from the laser parameters for irradiating at least a portion of the second area, and the laser parameters include laser power density and laser irradiation time.

[0007] As a further example, the first region and the second region correspond to a passivation contact region and a passivation non-contact region, respectively;

[0008] Alternatively, the first region and the second region correspond to two regions with opposite conductivity types.

[0009] As a further example, the adjacent first region and the second region are not irradiated with laser at the same time.

[0010] As a further example, the laser includes a first laser beam and a second laser beam, and the first laser beam is first used to irradiate the first area, and then the second laser beam is used to irradiate the second area.

[0011] As a further example, a first semiconductor layer is disposed in the first region, and a second semiconductor layer is disposed in the second region, and the conductivity type of the first semiconductor layer is opposite to that of the second semiconductor layer; one of the first semiconductor layer and the second semiconductor layer includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding laser power density is 6 W / cm 2 ~9W / cm 2 The laser irradiation time is 5s to 10s, and the other semiconductor layer includes doped polysilicon, and the corresponding laser power density is 1W / cm 2 ~5W / cm 2 , laser irradiation time is 5s to 15s;

[0012] Alternatively, one of the first semiconductor layer and the second semiconductor layer comprises doped amorphous silicon and / or microcrystalline silicon, and the corresponding laser power density is 5 W / cm 2 ~6W / cm 2 The laser irradiation time is 5s to 10s, and the other semiconductor layer includes doped polysilicon, and the corresponding laser power density is 5W / cm 2 ~6W / cm 2 , laser irradiation time is 11s~15s;

[0013] Or, one of the semiconductor layers includes N-type doped polysilicon, and the corresponding laser power density is 1 W / cm 2 ~5W / cm 2 The laser irradiation time is 5s to 10s, and the other semiconductor layer includes a P-type silicon substrate, and the corresponding laser power density is 6W / cm 2 ~9W / cm 2 , laser irradiation time is 5s to 15s;

[0014] Or, one of the semiconductor layers includes N-type doped polysilicon, and the corresponding laser power density is 4 W / cm 2 ~6W / cm 2 The laser irradiation time is 5s to 8s, and the other semiconductor layer includes a P-type silicon substrate, and the corresponding laser power density is 4W / cm 2 ~6W / cm 2 , laser irradiation time is 9s~15s;

[0015] Or, one of the semiconductor layers includes doped polysilicon, and the corresponding laser power density is 2 W / cm 2~5W / cm 2 The laser irradiation time is 5s to 15s, and the other semiconductor layer includes a perovskite layer, and the corresponding laser power density is 0.5W / cm 2 ~1W / cm 2 , laser irradiation time is 10s~20s

[0016] Or, one of the semiconductor layers includes doped polysilicon, and the corresponding laser power density is 1 W / cm 2 ~2W / cm 2 The laser irradiation time is 10 to 15 seconds, and the other semiconductor layer includes a perovskite layer, and the corresponding laser power density is 1W / cm 2 ~2W / cm 2 , the laser irradiation time is 16s~20s.

[0017] As a further example, one of the first region and the second region includes doped polysilicon, and the corresponding laser power density is 1 W / cm 2 ~6W / cm 2 , laser irradiation time is 5s to 15s;

[0018] Or, one of the first region and the second region includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding laser power density is 5 W / cm 2 ~9W / cm 2 , laser irradiation time is 5s~10s;

[0019] Alternatively, when one of the first region and the second region only includes the doped silicon substrate and the passivation layer, the corresponding laser power density is 4 W / cm 2 ~9W / cm 2 , laser irradiation time is 5s to 15s;

[0020] Or, one of the first region and the second region includes a perovskite layer, and the corresponding laser power density is 0.5 W / cm 2 ~2W / cm 2 , the laser irradiation time is 10s to 20s.

[0021] As a further example, the first region is heated while the first region is irradiated with laser, and / or the second region is heated while the second region is irradiated with laser.

[0022] As a further example, a first semiconductor layer is disposed in the first region, and a second semiconductor layer is disposed in the second region, and the conductivity type of the first semiconductor layer is opposite to that of the second semiconductor layer; one of the first semiconductor layer and the second semiconductor layer includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding heating temperature thereof is 150° C. to 300° C., and the other semiconductor layer includes doped polycrystalline silicon, and the corresponding heating temperature thereof is 200° C. to 300° C.;

[0023] Or, one of the semiconductor layers includes N-type doped polysilicon, and the corresponding heating temperature is 200° C. to 300° C., and the other semiconductor layer includes a P-type silicon substrate, and the corresponding heating temperature is 200° C. to 300° C.;

[0024] Alternatively, one of the semiconductor layers includes doped polysilicon, and the corresponding heating temperature is 200°C to 300°C, and the other semiconductor layer includes a perovskite layer, and the corresponding heating temperature is 100°C to 150°C.

[0025] As a further example, one of the first region and the second region includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding heating temperature is 150° C. to 300° C.;

[0026] Or, one of the first region and the second region includes doped polysilicon, and the corresponding heating temperature is 200° C. to 350° C.;

[0027] Or, when one of the first region and the second region only includes the doped silicon substrate and the passivation layer, the corresponding heating temperature is 200° C. to 350° C.;

[0028] Alternatively, one of the first region and the second region includes a perovskite layer, and the corresponding heating temperature is 100° C. to 150° C.

[0029] As a further example, the first region and the second region are heated by a heating surface, the solar cell is placed on the heating surface, and the side having the first region and the second region faces the heating surface; the heating surface includes at least one first heating zone and at least one second heating zone, and when laser irradiation occurs, the first heating zone is used to heat the first region, and the second heating zone is used to heat the second region.

[0030] As a further example, the heating table includes a first heating table and a second heating table located at two different positions, the first heating table includes a plurality of the first heating zones arranged at intervals, and the second heating table includes a plurality of the second heating zones arranged at intervals;

[0031] The first region and the second region are heated separately. After the first region is annealed on the first heating stage, the solar cell is transferred to the second heating stage to anneal the second region.

[0032] As a further example, the laser includes a first laser beam and a second laser beam. The first laser beam is used to irradiate the first area, and the second laser beam is used to irradiate the second area. The first laser beam and the second laser beam are both formed into multiple split beams through a beam splitter. The multiple split beams formed by splitting the first laser beam simultaneously irradiate multiple first areas with lasers, and the multiple split beams formed by splitting the second laser beam simultaneously irradiate multiple second areas with lasers.

[0033] As a further example, the laser spot of the laser is a spliced ​​spot or a linear spot, the size of the spliced ​​spot is smaller than the size of the solar cell, the spliced ​​spot includes any one or more of a rectangular spot or a circular spot, and the length of the linear spot is greater than the length or width direction of the solar cell.

[0034] As a further example, the laser power density or the laser irradiation time of the laser irradiating the first region or the second region is zero.

[0035] According to another aspect of the present invention, a solar cell annealing device is provided, which uses any of the above-mentioned solar cell annealing methods to anneal the solar cell.

[0036] According to another aspect of the present invention, a solar cell annealing device is provided, comprising:

[0037] A heating table, used for carrying and heating a solar cell having two different sub-regions on the same surface, wherein the solar cell comprises at least one first region and at least one second region located on the same surface, and the first region is different from the second region;

[0038] A laser processing module is located above the heating table, and the laser processing module is used for the heating table to heat the solar cell while irradiating the first area and the second area with laser; wherein at least one of the laser parameters irradiating at least a portion of the first area is different from the laser parameters irradiating at least a portion of the second area, and the laser parameters include laser power density and laser irradiation time.

[0039] As a further example, the heating table includes a first heating zone and a second heating zone that are staggered or alternately arranged. When the solar cell is placed on the heating table, the first heating zone is used to heat the first area, and the second heating zone is used to heat the second area; heating modules are provided in the first heating zone and the second heating zone.

[0040] As a further example, the heating table further includes a heat insulation zone located between the adjacent first heating zone and the second heating zone, and a first heat insulation board is disposed in the heat insulation zone.

[0041] As a further example, the heating table includes a first heating table and a second heating table that are independent of each other, the first heating table includes a plurality of first heating zones that are spaced apart, the second heating table includes a plurality of second heating zones that are spaced apart, the plurality of first heating zones and the plurality of second heating zones are arranged alternately, and the heating table also includes a first lifting mechanism connected to the first heating table and a second lifting mechanism connected to the second heating table.

[0042] According to another aspect of the present invention, a solar cell annealing device is provided, comprising:

[0043] A heating table, used for carrying and heating a solar cell including two different sub-areas on the same surface, wherein the solar cell includes at least one first area and at least one second area located on the same surface, and the first area is different from the second area; the heating table includes a first heating table and a second heating table located at a first station and a second station respectively, wherein the first heating table includes a plurality of first heating zones arranged at intervals, and the second heating table includes a plurality of second heating zones arranged at intervals;

[0044] A cell handling module, the cell handling module is used to transfer the solar cell from one heating platform to another heating platform;

[0045] A laser processing module is located above the heating table, and the laser processing module is used to heat the solar cell while irradiating the first area and the second area respectively with a first laser beam and a second laser beam; wherein at least one of the laser parameters irradiating at least a portion of the first area is different from the laser parameters irradiating at least a portion of the second area, and the laser parameters include laser power density and laser irradiation time; the laser processing module includes a first laser and a second laser respectively located above the first station and the second station, the first laser is used to emit the first laser beam, and the second laser is used to emit the second laser beam.

[0046] Compared with the prior art, the present invention adopts a selective laser annealing method for a solar cell including two different sub-regions on the same surface, adopts different laser process parameters for the two regions, and finally forms a good passivation effect in the two regions of the battery cell, thereby improving the fill factor FF of the solar cell. Laser selective annealing improves the contact resistance between the metal and silicon layers, reduces the series resistance Rs, and improves the open circuit voltage Voc. Laser selective annealing excites the overflow of H atoms in the passivation layer to passivate defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0048] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0049] Figure 1 A front view of a solar cell with a simplified structure provided in this application;

[0050] Figure 2 for Figure 1 A schematic diagram of the structure of the back side of a solar cell with a simplified structure shown;

[0051] Figure 3 A schematic structural diagram of a solar cell annealing device according to an embodiment of the present application;

[0052] Figure 4 A top view of a heating table provided in an embodiment of the present application;

[0053] Figure 5 A front view of a heating table provided in an embodiment of the present application;

[0054] Figure 6 A schematic structural diagram of a solar cell annealing device according to another embodiment of the present application;

[0055] Figure 7 A front view of another simplified solar cell provided in the present application.

[0056] Description of reference numerals:

[0057] 1-semiconductor substrate; 2-first semiconductor layer; 3-second semiconductor layer; 4-tunneling oxide layer; 5-third semiconductor layer; 6-passivation layer; 10-heating table; 11-first heating table; 12-second heating table; 20-laser processing module; 21-first laser; 22-second laser; 40-heating module; 50-second thermal insulation board; 60-cell handling module; 70-substrate;

[0058] A-first area; B-second area; C-isolation area; S1-first heating area; S2-second heating area; S3-insulation area;

[0059] X - first direction. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the embodiments in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0061] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0062] The applicant has found that for a solar cell with two different sub-regions on the same surface, the optimal annealing conditions for the two sub-regions are different due to the differences between the two sub-regions, and the current existing technology still uses a full-width annealing method, which will lead to incompatibility of annealing processes for different sub-regions of the solar cell, so that the overall performance of the cell cannot be well improved. In addition, with the gradual development of photovoltaic technology, the structure of solar cells is becoming more and more complex, and the disadvantage of using a full-width annealing method to process a solar cell with two different sub-regions on the same surface will become more and more obvious.

[0063] In this application, the two sub-regions of the solar cell are different, which means that the structures of the two sub-regions are different. Specifically, it can be considered that the materials of the two sub-regions are different, or the number of film layers set in the sub-regions is different, or the film thickness is different. More specifically, the different materials can be different types of materials, or different temperature thresholds of the materials, or different crystallization rates of the materials. The temperature threshold of the material refers to the temperature that the material can withstand.

[0064] For a solar cell, a sub-region includes at least a passivation layer located on the surface of the cell. The passivation layer may be, for example, a single layer or a multilayer film of any combination, such as SiNx Single layer film, or AlO x With SiN x Multilayer film, or SiON x With SiN x In addition, a sub-region may also include a semiconductor layer in contact with the electrode, and the semiconductor layer may be at least one material of doped polysilicon material, amorphous silicon material, microcrystalline silicon material, perovskite material, Si material, organic material, etc. When the sub-region includes a semiconductor layer, a passivation layer is provided on the surface of the semiconductor layer away from the semiconductor substrate. The specific structure of a sub-region is determined by the type of solar cell.

[0065] It should be noted that the solar cell having two different sub-regions on the same surface can be a double-sided electrode type solar cell (i.e., the positive electrode and the negative electrode are located on the front and back of the cell, such as a TOPCon cell) or a back contact solar cell (i.e., the positive electrode and the negative electrode are both located on the back of the cell, such as a BC cell). The most typical back contact solar cell is a back P region and a back N region using a TOPCon cell and a HJT cell structure, respectively, but is of course not limited to the above examples.

[0066] Based on the problems existing in the prior art, the present invention provides an annealing method and an annealing device for a solar cell. For a solar cell including two different sub-regions on the same surface, matching laser annealing parameters are selected respectively to achieve the optimal passivation effect of each of the two sub-regions.

[0067] Specifically, the present application proposes an annealing method for a solar cell, which is applied to a solar cell including two different sub-regions on the same surface, wherein the solar cell includes at least one first region and at least one second region located on the same surface, and the first region is different from the second region, wherein the number of the first region and the second region can be multiple, and the first region and the second region can be on the front side or the back side of a double-sided electrode type solar cell, or on the back side of a back contact solar cell.

[0068] Furthermore, the first region and the second region may correspond to a passivation contact region and a passivation non-contact region, respectively. In this case, the solar cell may be a double-sided electrode type solar cell or a back contact solar cell, preferably a back contact solar cell. The passivation contact region refers to a region of a semiconductor layer that contacts the electrode of the solar cell, and the electrode will be arranged in this region. The passivation non-contact region refers to a region outside the passivation contact region on the same side of the battery. Alternatively, the first region and the second region may also correspond to two regions of opposite conductivity types. In this case, the solar cell is a back contact solar cell. The first region and the second region may also be referred to as the P region and the N region of the back contact solar cell. The first region and the second region may correspond to one and the other of the positive electrode and the negative electrode.

[0069] like Figure 1 A front view of a simplified structure of a solar cell is shown. Figure 2 for Figure 1 The schematic diagram of the back side of the solar cell with a simplified structure is shown. Figure 1 and Figure 2 The solar cell shown is a back-contact solar cell. The first region A and the second region B in the figure correspond to two regions of opposite conductivity types. The first region A is different from the second region B. The solar cell includes a semiconductor substrate 1, a first semiconductor layer 2, a second semiconductor layer 3, a first electrode and a second electrode (not shown in the figure). The semiconductor substrate 1 has a relative front and back surface. The back surface includes a first region A and a second region B arranged in an interdigitated manner. The first semiconductor layer 2 is arranged in the first region A, and the second semiconductor layer 3 is arranged in the second region B. The conductivity types of the first semiconductor layer 2 and the second semiconductor layer 3 are opposite. The first electrode is arranged on the first semiconductor layer 2 in the first region A, and the second electrode is arranged on the second semiconductor layer 3 in the second region B. Among them, the number of the first region A and the second region B are both multiple. Further, Figure 1 In the back contact solar cell shown in FIG. 1 , the first region A and the second region B can be considered to be arranged alternately along a first direction. Figure 1 The X-axis direction.

[0070] It should be noted that other functional film layers can also be arranged in the first region A and the second region B to ensure that the first electrode and the second electrode finally contact the first semiconductor layer 2 and the second semiconductor layer 3 respectively. For example, the solar cell at least includes a first passivation layer arranged in the first region A and a second passivation layer arranged in the second region B, the first passivation layer and the first semiconductor layer 2 are arranged in sequence along a direction away from the semiconductor substrate 1, and the second passivation layer and the second semiconductor layer 3 are arranged in sequence along a direction away from the semiconductor substrate 1.

[0071] The back side of the back-contact solar cell also includes an isolation region C located between adjacent first regions A and second regions B. In this embodiment, the first regions A and second regions B are spaced apart, and the isolation region C is the region between adjacent first regions A and second regions B.

[0072] It should also be noted that there is more than one form of isolation between the first semiconductor layer 2 and the second semiconductor layer 3. For example, as another case, the first region A and the second region B can also be arranged in contact. In this case, in the first direction, the second passivation layer and the second semiconductor layer 3 at least partially extend to the first region A, and the first orthographic projection of the first passivation layer and the first semiconductor layer 2 on the semiconductor substrate 1 overlaps at least partially with the second orthographic projection of the second passivation layer and the second semiconductor layer 3 on the semiconductor substrate 1. Further, a first conductive layer is arranged on the surface of the first semiconductor layer 2 away from the semiconductor substrate 1, and a second conductive layer is arranged on the surface of the second semiconductor layer 3 away from the semiconductor substrate 1. The first electrode is arranged on the first conductive layer, and the second electrode is arranged on the second conductive layer, and the first conductive layer and the second conductive layer are disconnected from each other. In this case, the isolation region C is the region where the first conductive layer and the second conductive layer are disconnected. Considering that the types and isolation forms of the back contact battery may be more than the types listed above, and the specific structure and formation process of the back contact solar cell are not the focus of this application, they will not be repeated here.

[0073] For back-contact solar cells, the first region A can be either a P region or an N region in the field of solar cells. When the first region A is a P region, the second region B is an N region; when the first region A is an N region, the second region B is a P region.

[0074] Among them, the semiconductor substrate 1 may include materials such as single crystal silicon, germanium or gallium arsenide. The specific materials and annealing conditions of the first semiconductor layer 2 and the second semiconductor layer 3 depend on the specific structure of the solar cell. For example, when the first region A and the second region B adopt the passivation structure of the TOPCon cell and the HJT cell, the material of the first semiconductor layer 2 may include doped polycrystalline silicon with a thickness ranging from 10nm to 250nm, and the first passivation layer includes a tunneling oxide; the second semiconductor layer 3 includes doped amorphous silicon and / or microcrystalline silicon with a thickness ranging from 1nm to 60nm, and the second passivation layer includes intrinsic amorphous silicon. For another example, the first semiconductor layer 2 includes doped polycrystalline silicon, and the second semiconductor layer 3 includes a silicon substrate; or, the first semiconductor layer 2 includes doped polycrystalline silicon, and the second semiconductor layer 3 includes a perovskite layer, and the second semiconductor layer 3 also includes an electron transport layer and a hole transport layer located on the front and back sides of the perovskite layer.

[0075] like Figure 7As shown, a front view of another simplified structure of a solar cell, the solar cell in this figure is a double-sided electrode type TOPCon cell, and the figure shows that a local area on the back side includes a poly-doped polycrystalline silicon structure. At this time, the TOPCon cell includes an N-type semiconductor substrate 1, and the back side of the semiconductor substrate 1 includes a plurality of first regions A and a plurality of second regions B. The structures of the first region A and the second region B are different. The first region A corresponds to a passivation contact area. Along the direction away from the semiconductor substrate 1, the first region A includes a tunneling oxide layer 4, a third semiconductor layer 5, and a passivation layer 6 arranged in sequence. The second region B corresponds to a passivation non-contact area, including an N-type doped silicon substrate (semiconductor substrate 1) and a passivation layer 6, wherein the third semiconductor layer 5 is a doped polycrystalline silicon layer, and the passivation layer 6 can be SiN x 、SiON x In this embodiment, the laser power density of the first region A can be set to 1 W / cm 2 ~5W / cm 2 The laser irradiation time is 5s to 10s, the heating temperature is 200℃ to 250℃; the laser power density of the second area B is 6W / cm 2 ~9W / cm 2 , the laser irradiation time is 5s~15s, and the heating temperature is set to 200℃~250℃.

[0076] For a solar cell having two different sub-regions on the same surface, the annealing method of the solar cell proposed by the present invention includes:

[0077] Laser is used to irradiate the first area A and the second area B; wherein at least one of the laser parameters for irradiating at least a portion of the first area A and the laser parameters for irradiating at least a portion of the second area B is different, and the laser parameters include laser power density and laser irradiation time.

[0078] Specifically, the laser used includes a first laser beam and a second laser beam, the first laser beam is used to irradiate the first region A, and the second laser beam is used to irradiate the second region B. Different laser parameters mean that the laser power density irradiating the two semiconductor regions may be different, the laser irradiation time may be different, or both may be different.

[0079] The present invention adopts a selective laser annealing method and adopts different laser process parameters for two different sub-regions, so that both regions of the battery cell form a good passivation effect, thereby improving the fill factor FF of the solar cell. Laser selective annealing improves the contact resistance between the metal and silicon layers and reduces the series resistance Rs; the open circuit voltage Voc is increased. Laser selective annealing excites the overflow of H atoms in the passivation layer to passivate defects.

[0080] In addition, compared with the traditional tunnel-type LED light injection annealing furnace that anneals the front and back sides of the cell substrate at the same time, since the laser is a selective annealing method, this patent also has the advantages of annealing a local area on a single side of the cell without affecting other areas far away from the surface, and avoiding thermal effects on the other side of the cell.

[0081] Specifically, when laser irradiation is performed, the first area A and the second area B can be irradiated separately in a sequence, or the first area A and the second area B can be irradiated simultaneously. Preferably, the adjacent first area A and the second area B are not irradiated with laser at the same time. Among them, the specific implementation method of annealing separately in a sequence can be found below. When two sub-areas are annealed at the same time, in order to avoid the mutual influence of the two adjacent sub-areas, there are many ways to choose, for example, one of which is to divide all sub-areas into left and right parts, and in the first step, the first area A on the left part and the second area B on the right part are irradiated with laser, and in the second step, the first area A on the right part and the second area B on the left part are irradiated with laser.

[0082] Further preferably, the first laser beam is first used to irradiate the first area A, and then the second laser beam is used to irradiate the second area B. This method is easier to operate and control, and can also avoid mutual influence between two adjacent sub-areas.

[0083] Specifically, when the first laser beam is used to irradiate the first region A and the second laser beam is used to irradiate the second region B, the orientation of the laser irradiation on the cell is not limited. For example, when the first region A and the second region B are located on the back of the cell, the laser can irradiate the first region A and the second region B from the back or from the front through the semiconductor substrate 1. When the laser irradiates the first region A and the second region B, the laser is not limited to irradiating only the surface of the cell.

[0084] Among them, the laser parameters for irradiating at least part of the first region A are different from the laser parameters for irradiating at least part of the second region B, which means that the laser parameters for irradiating all the first regions A are different from the laser parameters for irradiating all the second regions B; or the laser parameters for irradiating part of the first region A are different from the laser parameters for irradiating part of the second region B. The latter case is considered that, for example, the first region A (or second region B) at the edge position and the middle position of the solar cell may have slightly different process performance due to the preparation process or other reasons, such as different thickness. At this time, in order to better achieve the annealing effect of all sub-regions, the laser parameters for irradiating part of the first region A may be the same as the laser parameters for irradiating part of the second region B.

[0085] As another embodiment, the following illustrates several specific laser parameters when different functional layer materials are used in the first region A and the second region B. Specifically, a first semiconductor layer is provided in the first region A, and a second semiconductor layer is provided in the second region B. The conductivity types of the first semiconductor layer and the second semiconductor layer are opposite; for example, one of the first semiconductor layer and the second semiconductor layer includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding laser power density is 6W / cm 2 ~9W / cm 2 The laser irradiation time is 5s to 10s, and the other semiconductor layer includes doped polysilicon, and the corresponding laser power density is 1W / cm 2 ~5W / cm 2 , laser irradiation time is 5s to 15s;

[0086] Alternatively, one of the first semiconductor layer and the second semiconductor layer includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding laser power density is 5 W / cm 2 ~6W / cm 2 The laser irradiation time is 5s to 10s, and the other semiconductor layer includes doped polysilicon, and the corresponding laser power density is 5W / cm 2 ~6W / cm 2 , laser irradiation time is 11s~15s;

[0087] Or, one of the semiconductor layers includes N-type doped polysilicon, and the corresponding laser power density is 1 W / cm 2 ~5W / cm 2 The laser irradiation time is 5s to 10s, and the other semiconductor layer includes a P-type silicon substrate, and the corresponding laser power density is 6W / cm 2 ~9W / cm 2 , laser irradiation time is 5s to 15s;

[0088] Or, one of the semiconductor layers includes N-type doped polysilicon, and the corresponding laser power density is 4 W / cm 2 ~6W / cm 2 The laser irradiation time is 5s to 8s, and the other semiconductor layer includes a P-type silicon substrate, and the corresponding laser power density is 4W / cm 2 ~6W / cm 2 , laser irradiation time is 9s~15s;

[0089] Or, one of the semiconductor layers includes doped polysilicon, and the corresponding laser power density is 2 W / cm 2 ~5W / cm 2The laser irradiation time is 5s to 15s, and the other semiconductor layer includes a perovskite layer, and the corresponding laser power density is 0.5W / cm 2 ~1W / cm 2 , laser irradiation time is 10s~20s

[0090] Or, one of the semiconductor layers includes doped polysilicon, and the corresponding laser power density is 1 W / cm 2 ~2W / cm 2 The laser irradiation time is 10 to 15 seconds, and the other semiconductor layer includes a perovskite layer, and the corresponding laser power density is 1W / cm 2 ~2W / cm 2 , the laser irradiation time is 16s to 20s. The above parameter conditions can achieve good annealing effect.

[0091] As another embodiment, one of the first region A and the second region B includes doped polysilicon, and the corresponding laser power density is 1 W / cm 2 ~6W / cm 2 , the laser irradiation time is 5s to 15s; or, one of the first region A and the second region B includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding laser power density is 5W / cm 2 ~9W / cm 2 , the laser irradiation time is 5s to 10s; or, when one of the first region A and the second region B only includes the doped silicon substrate and the passivation layer, the corresponding laser power density is 4W / cm 2 ~9W / cm 2 , the laser irradiation time is 5s to 15s; or, one of the first region A and the second region B includes a perovskite layer, and the corresponding laser power density is 0.5W / cm 2 ~2W / cm 2 , the laser irradiation time is 10s to 20s. By controlling the laser parameters within the above corresponding range, both the first region and the second region can obtain better annealing effects.

[0092] It should be noted that the laser parameter conditions of a sub-area need to comprehensively consider the laser tolerance of each material in the area.

[0093] When one of the above regions includes doped polysilicon, doped amorphous silicon and / or microcrystalline silicon, or a perovskite layer, when it is used as the semiconductor layer of the region (in contact with the electrode), the laser parameters of the region (these three semiconductor layers have low tolerance to laser); and when one of the above regions only includes a doped silicon substrate and a passivation layer, the doped silicon substrate can be used as a semiconductor layer, such as the HPBC battery below, or as a substrate of a passivated non-contact region, such as a TOPCon battery. In these two cases, the above laser annealing parameters (laser power density is 4W / cm 2 ~9W / cm 2 Of course, when the doped silicon substrate is used as the semiconductor layer, this region also includes the electrode in contact with the doped silicon substrate.

[0094] As another embodiment, the first region A is heated while the laser is irradiated therewith, and / or the second region B is heated while the laser is irradiated therewith. By heating the region while the laser is irradiating its corresponding region, the laser annealing effect is improved.

[0095] Furthermore, there are multiple ways to heat the first region A and the second region B, one of which is to heat the first region A and the second region B at the same time, and maintain the heating temperature at the lower heating temperature required in the two semiconductor regions. When the heating temperatures required for the two regions are the same, they are the same temperature. Or the second way, in order to achieve a better annealing effect, the first region A and the second region B are not heated at the same time, and the heating temperatures of the two regions are set to be different. Specifically, when the first laser beam is used to irradiate the first region A, the heating temperature of the first region A is the first temperature; when the second laser beam is used to irradiate the second region B, the heating temperature of the second region B is the second temperature, and the first temperature is different from the second temperature. By heating the two regions at the same time and at different heating temperatures, it is beneficial to more accurately control the preheating of the two regions to a more suitable temperature, thereby improving the overall annealing effect. Or the third way is to heat the first region A and the second region B at the same time, and the heating temperatures are different, which can be set according to actual conditions.

[0096] Furthermore, in order to prevent the adjacent first region A and second region B from influencing each other during laser annealing, the adjacent first region A and second region B are subjected to heat insulation treatment, for example, a first heat insulation board is provided in the heating table described below. For a back contact solar cell, when it has an isolation region, a first heat insulation board is provided at a position corresponding to the isolation region.

[0097] As another embodiment, the following illustrates several specific heating temperature ranges when the first region A and the second region B use different functional layer materials. A first semiconductor layer is provided in the first region A, and a second semiconductor layer is provided in the second region B. The conductivity types of the first semiconductor layer and the second semiconductor layer are opposite. One of the first semiconductor layer and the second semiconductor layer includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding heating temperature is 150° C. to 300° C., and the other semiconductor layer includes doped polycrystalline silicon, and the corresponding heating temperature is 200° C. to 300° C.;

[0098] Or, one of the semiconductor layers includes N-type doped polysilicon, and the corresponding heating temperature is 200° C. to 300° C., and the other semiconductor layer includes a P-type silicon substrate, and the corresponding heating temperature is 200° C. to 300° C.;

[0099] Alternatively, one of the semiconductor layers includes only doped polysilicon and a passivation layer, and the corresponding heating temperature is 200°C to 300°C, and the other semiconductor layer includes a perovskite layer, and the corresponding heating temperature is 100°C to 150°C.

[0100] It should be noted that when the sub-region is heated while being irradiated with laser, the heating temperature is maintained for at least the laser irradiation time in the above example.

[0101] As another embodiment, one of the first region A and the second region B includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding heating temperature is 150°C to 300°C; or, one of the first region A and the second region B includes doped polysilicon, and the corresponding heating temperature is 200°C to 300°C; or, one of the first region A and the second region B includes a doped silicon substrate, and the corresponding heating temperature is 200°C to 300°C; or, one of the first region A and the second region B includes a perovskite layer, and the corresponding heating temperature is 100°C to 150°C. Controlling the heating temperature of each of the two sub-regions within the above corresponding ranges helps the solar cell to obtain a better annealing effect.

[0102] As another embodiment, the first area A and the second area B on the same side of the solar cell are heated by a heating table, and the solar cell is placed on the heating table, with the side having the first area A and the second area B facing the heating table; the heating table includes at least one first heating zone S1 and at least one second heating zone S2, and during laser irradiation, the first heating zone S1 is used to heat the first area A, and the second heating zone S2 is used to heat the second area B; when there are multiple first areas A and multiple second areas B respectively, it is preferred that the first heating zones S1 are opposite to the first areas A one by one, and the second heating zones S2 are opposite to the second areas B one by one.

[0103] Depending on whether the heating method used is to heat the two sub-areas simultaneously or not, the working modes of the two heating zones may be different. When the first zone A and the second zone B are heated simultaneously: the first heating zone S1 and the second heating zone S2 work simultaneously, preferably at this time, the heating temperature of the first heating zone S1 and the second heating zone S2 are the same, and at this time, it is preferred to heat at one station and one heating table, without the need to separately divide the first heating zone S1 and the second heating zone S2 on the heating table.

[0104] When the first area A and the second area B are not heated at the same time: the heating temperatures of the two areas can be the same or different. It is preferred that the heating temperatures of the two areas are different, so that the annealing effect is better. In a more specific example, when the first area A is heated, the first heating zone S1 works, and the second heating zone S2 does not work; when the second area B is heated, the first heating zone S1 does not work, and the second heating zone S2 works, and the heating temperatures of the two heating zones are different. At this time, annealing can be completed in one workstation or in two workstations. In one workstation, the heating table surface can also have a variety of structures, which can be one heating table or two tables. Figure 4 This application provides a top view of a heating table when heating is not performed simultaneously at one workstation. For details, please refer to the detailed description of the heating table below.

[0105] As another example, Figure 6 The schematic diagram of the structure of the annealing device of the solar cell provided in the present application shows that when the annealing is completed at two different stations, the heating table 10 includes a first heating table 11 and a second heating table 12 located at the two stations, the first heating table 11 includes a plurality of first heating zones S1 arranged at intervals, and the second heating table 12 includes a plurality of second heating zones S2 arranged at intervals; the first area A and the second area B are heated separately, and after the first area A is annealed on the first heating table 11, the solar cell is transferred to the second heating table 12 for annealing of the second area B. This annealing method of two sub-areas in two stations without performing the annealing at the same time is conducive to the implementation and control of different heating temperatures, and is more convenient for mass production.

[0106] As another embodiment, a first laser beam is used to irradiate a first region A, and a second laser beam is used to irradiate a second region B. The first laser beam and the second laser beam are both formed into a plurality of split beams through a beam splitter. The plurality of split beams formed by the splitting of the first laser beam simultaneously irradiate a plurality of first regions A with lasers, and the plurality of split beams formed by the splitting of the second laser beam simultaneously irradiate a plurality of second regions B with lasers, thereby improving processing efficiency. Furthermore, the number of split beams is greater than or equal to the number of all first regions A or second regions B, thereby further improving work efficiency.

[0107] It should also be noted that there is a situation where the first laser beam and the second laser beam can originate from the same laser, for example, the laser beam emitted by the laser is divided into two split beams with different laser powers by a laser splitter, wherein the splitter used can be selected to have the characteristic of splitting the laser beam into split beams with different power densities. In addition, the first laser beam and the second laser beam can also be obtained by switching different working modes of the same laser.

[0108] As another embodiment, the laser spot of the laser, that is, the laser spot of the first laser beam and the second laser beam, is a spliced ​​spot or a linear spot. The size of the spliced ​​spot is smaller than the size of the solar cell. The spliced ​​spot includes any one or more of a rectangular spot or a circular spot. At this time, when the laser irradiates the first area A and the second area B, it can be completed by splicing the laser spot; the length of the linear spot is greater than the size of the solar cell in the length or width direction. At this time, when the laser irradiates the first area A and the second area B, there is no need to splice, and the irradiation can be completed by scanning in a direction perpendicular to the length direction of the linear spot. When the laser spot is a linear spot, the processing efficiency is higher.

[0109] As another embodiment, the laser power density or laser irradiation time of the first area A or the second area B is 0. That is, in this embodiment, only one of the sub-areas is irradiated with laser, and the other sub-area does not need to be irradiated with laser. This method is suitable for application scenarios where only one of the sub-areas needs to be improved, and the performance or passivation effect of the sub-area irradiated by laser is further improved.

[0110] Furthermore, the specific laser parameters of the laser irradiating the sub-region, whether to heat the sub-region, and the heating temperature are determined according to the structure and material of the film layer in the sub-region. The corresponding heating table 10 in this case refers to the description of the heating table 10 in this application, except that only one heating zone needs to be set, preferably in one station.

[0111] The present invention further provides a solar cell annealing device, which uses the solar cell annealing method described in any of the above embodiments to anneal the solar cell.

[0112] The present invention also provides a solar cell annealing device, such as Figure 3 As shown, including:

[0113] The heating table 10 is used to carry and heat a solar cell including two different sub-regions on the same surface, wherein the solar cell includes at least one first region A and at least one second region B located on the same surface, and the first region A is different from the second region B; preferably, the surface having the first region A and the second region B faces the heating table 10. For ease of description, the following embodiment takes the back surface of the back-contact solar cell including the first region A and the second region B alternately arranged along the first direction and the isolation region C located between the adjacent first region A and the second region B as an example for detailed description.

[0114] The laser processing module 20 is located above the heating table 10. The laser processing module 20 is used to heat the table 10 to heat the solar cell while using lasers, that is, the first laser beam and the second laser beam to irradiate the first area A and the second area B respectively; wherein, at least one of the laser parameters irradiating at least a portion of the first area A and the laser parameters irradiating at least a portion of the second area B is different, and the laser parameters include laser power density and laser irradiation time. As described in the above embodiment, the first area and the second area can be irradiated with lasers at the same time or at different times, and the first area can be heated at the same time or at different times, or only one of the areas can be heated.

[0115] Specifically, the laser processing module 20 includes a laser for emitting a laser beam and a laser scanning mechanism for controlling the scanning direction of the laser beam. The laser scanning mechanism includes, for example, a galvanometer and a field mirror. Of course, if there are shaping or other requirements, the laser processing module 20 may also include, for example, a shaping device or other optical elements. Considering that the laser processing module 20 needs to emit two laser beams with different laser parameters, the laser processing module 20 may use either one laser or two lasers. When one laser is used, the laser working mode may be directly switched to achieve, for example, different laser power density requirements. Of course, two lasers may also be used, such as Figure 6 As shown, at this time, two stations are working, one station corresponds to one laser, and the laser parameters of the two lasers are different. In other words, two lasers are used in one station, and the two lasers emit laser beams with different laser parameters respectively.

[0116] Through the annealing device of the solar cell, selective laser annealing can be adopted to use different laser process parameters for two different sub-regions, so that the two different sub-regions can both form a good passivation effect, effectively realizing the laser annealing of the solar cell and improving the annealing process effect.

[0117] The specific structure of the heating table 10 can have multiple situations depending on whether the heating method used is to heat the two sub-areas simultaneously or not. When the first area A and the second area B are heated simultaneously and the heating temperatures of the two areas are the same: at this time, it is only necessary for the table to have a heating function and be able to control it within the required heating temperature range. At this time, one station and one table are sufficient. At this time, the heating table 10 does not need to be divided into two heating zones, and is suitable for both BC batteries and TOPCon batteries.

[0118] Of course, the heating temperatures of the two areas may also be different. The heating table 10 further includes a staggered or alternately arranged first heating zone S1 and a second heating zone S2. When the first heating zone S1 and the second heating zone S2 are staggered, they are suitable for batteries in which the first area A and the second area B correspond to the passivation contact area and the passivation non-contact area, respectively; when the first heating zone S1 and the second heating zone S2 are alternately arranged, they are suitable for two areas with opposite conductivity types corresponding to the first area A and the second area B. When the solar cell is placed on the heating table 10, the first heating zone S1 faces the first area A, and the first heating zone S1 is used to heat the first area A. The second heating zone S2 faces the second area B, and the second heating zone S2 is used to heat the second area B. A heating module 40 is provided in the first heating zone S1 and the second heating zone S2. Among them, the heating module 40 is, for example, a heating component such as a heating wire. Of course, other structures that can be heated are also within the protection scope of the present invention.

[0119] Specifically, a heating module 40 is provided in each first heating zone S1 and each second heating zone S2. In order to facilitate wiring and power connection, all the heating modules 40 of the first heating zones S1 can be connected in series and then connected to an external power supply, or all the heating modules 40 of the second heating zones S2 can be connected in series and then connected to an external power supply.

[0120] Figure 4 , Figure 5 FIG. 1 is a schematic diagram of a heating table 10 according to one embodiment of the present invention.

[0121] Furthermore, the heating table 10 also includes an insulation area S3 located between the adjacent first heating area S1 and the second heating area S2, and a first insulation board (not numbered in the figure) is arranged in the insulation area S3. By arranging the first insulation board with good insulation effect, when the two heating areas work independently, heat will not be transferred to each other, which helps to avoid the heat transfer from the heating table 10 to another area when the heating back contacts one area of ​​the solar cell. This structure can achieve different heating temperatures in two areas at one workstation. Preferably, when the heating temperatures of the two sub-areas are different, a first insulation board is arranged, which is suitable for having an isolation area between the adjacent first area A and the second area B of the solar cell.

[0122] Furthermore, the heating table 10 includes a heating layer, a second heat insulating plate 50 and a substrate 70 in sequence along its thickness direction. The second heat insulating plate 50 covers the entire heating layer. The first heating zone S1 and the second heating zone S2 constitute the heating layer. When there is a heat insulating zone S3, the first heating zone S1, the second heating zone S2 and the heat insulating zone S3 constitute the heating layer. By providing the second heat insulating plate 50, the heating layer is isolated from the substrate 70 to prevent the entire heating table 10 from being overheated.

[0123] When the first area A and the second area B are heated at different temperatures and not at the same time, as another example, the two heating zones can also be raised and lowered in correspondence with the heating table. The specific structure is that the heating table 10 includes a first heating table 11 and a second heating table 12 that are independent of each other, the first heating table 11 includes a plurality of first heating zones S1 arranged at intervals, the second heating table 12 includes a plurality of second heating zones S2 arranged at intervals, and the plurality of first heating zones S1 and the plurality of second heating zones S2 are arranged alternately, and the heating table 10 also includes a first lifting mechanism connected to the first heating table 11 and a second lifting mechanism connected to the second heating table 12. This embodiment can also be implemented in one station. During operation, the two heating tables work separately. When the first heating table 11 heats the first area A, the second lifting mechanism drives the second heating table 12 to descend without contacting the battery; when the second heating table 12 heats the second area B, the first lifting mechanism drives the first heating table 11 to descend without contacting the battery. Through this embodiment, non-simultaneous heating can also be achieved, which is also conducive to more accurately controlling the preheating of each sub-area to a more suitable temperature and improving the overall annealing effect.

[0124] When the first region A and the second region B are not heated simultaneously, the heating can also be completed at two workstations. Specifically, the present invention further provides an annealing device for a solar cell, comprising:

[0125] The heating table 10 is used to carry and heat a solar cell having two different sub-regions on the same surface, wherein the solar cell comprises at least one first region A and at least one second region B located on the same surface, and the first region A is different from the second region B; preferably, the surface having the first region A and the second region B faces the heating table 10; for ease of description, the following embodiment takes the back surface of the back-contact solar cell including the first region A and the second region B alternately arranged along the first direction and the isolation region C located between the adjacent first region A and the second region B as an example for detailed description. Figure 6 The heating table 10 includes a first heating table 11 and a second heating table 12 respectively located at the first station and the second station, the first heating table 11 includes a plurality of first heating zones S1 arranged at intervals, and the second heating table 12 includes a plurality of second heating zones S2 arranged at intervals;

[0126] A cell handling module 60, which is used to transfer solar cells from one heating platform to another heating platform;

[0127] A laser processing module 20 is located above the heating table 10. The laser processing module 20 is used to heat the solar cell while using a first laser beam and a second laser beam to irradiate the first area A and the second area B respectively; wherein the laser parameters for irradiating at least a portion of the first area A are different from the laser parameters for irradiating at least a portion of the second area B; the laser processing module 20 includes a first laser 21 and a second laser 22 respectively located above the first station and the second station, the first laser 21 is used to emit the first laser beam, and the second laser 22 is used to emit the second laser beam.

[0128] Among them, during laser annealing, the first heating zone S1 is aligned with the first area A one by one, and the second heating zone S2 is aligned with the second area B one by one. When the first area A and the second area B are heated separately, for example, the first area A can be heated first, and the first heating zone S1 of the first heating table 11 works; then the battery is transferred from the first heating table 11 to the second heating table 12 through the battery cell handling module 60, and when the second area B is heated, the second heating zone S2 of the second heating table 12 works. Of course, the second area S2 can also be annealed first, and the order is not limited. This method of heating with two tables and two stations can not only effectively realize the annealing work of different sub-areas, but also facilitate mass production.

[0129] The cell handling module 60 can be a conventional structure in the prior art, such as a robot with a suction cup assembly. The laser processing module 20 can refer to the above description. Since this embodiment is divided into two stations, it preferably includes two lasers.

[0130] Example 1 (HPBC battery, Hybrid Passivated Back Contact, composite passivated back contact battery)

[0131] 1. Place the back contact solar cell on the heating table 10, with the light receiving surface facing upward; wherein the N region (second region B) is a phosphorus-doped polysilicon layer; the P region is a silicon substrate; turn on the heating of the N region, and the heating temperature is set to 200° C. to 250° C.;

[0132] 2. Use a CCD camera to capture the battery mark points, obtain the position data of the first area A and the second area B, and then transmit them to the laser control software;

[0133] 3. According to the acquired position data of the two semiconductor regions, the corresponding matching laser power and processing speed are set in the laser control software to accurately scan and process all N regions of the back contact solar cell; the heating is maintained during the laser irradiation process, the heating temperature is 200℃~250℃, and the laser power density is 1W / cm 2 ~5W / cm 2 , laser irradiation time is 5s~10s;

[0134] 4. Turn off the N-area heating and turn on the P-area (first area A) heating. The heating temperature is set to 200℃~250℃. Perform precise scanning and processing on all P-areas of the back contact solar cell. During the laser irradiation, the heating is maintained. The laser power density is 6W / cm 2 ~9W / cm 2 , the laser irradiation time is 5s to 15s.

[0135] More specifically, the laser wavelength used in the P region and the N region is 355nm to 1060nm; the laser spot can be any one of a rectangular flat-top spot, a circular flat-top spot, or a circular Gaussian spot. More specifically, the laser energy density used in the N region is 3W / cm 2 The laser irradiation time is 8s and the heating temperature is 220℃. The laser energy density used in the P zone is 8W / cm 2 , laser irradiation time is 8s, and heating temperature is 220℃.

[0136] Example 2 (HBC battery, Heterojunction Back Contact, heterojunction back contact battery)

[0137] 1. Place the back-contact solar cell on the heating table 10, with the light-receiving surface facing upward; the second semiconductor layer 3 in the N region is doped polycrystalline silicon, and the first semiconductor layer 2 in the P region is doped amorphous silicon and / or microcrystalline silicon. Turn on the heating of the P region (first region A), and set the heating temperature to 150°C to 200°C;

[0138] 2. Use a CCD camera to capture the battery mark points, obtain the position data of the first area A and the second area B, and then transmit them to the laser control software;

[0139] 3. According to the acquired position data of the two semiconductor regions, the corresponding matching laser power and processing speed are set in the laser control software to accurately scan and process all P regions of the back contact solar cell; the heating is maintained during the laser irradiation process, the heating temperature is 150℃~200℃, and the laser power density is 6W / cm 2 ~9W / cm 2 , laser irradiation time is 5s~10s;

[0140] 4. After the P zone annealing is completed, turn off the P zone heating and turn on the N zone (second zone B) heating. The heating temperature is set to 200℃~250℃. Perform precise scanning processing on all N zones of the back contact solar cell. During the laser irradiation, the heating is maintained. The laser power density is 1W / cm 2 ~5W / cm 2 , the laser irradiation time is 5s to 15s.

[0141] More specifically, the laser wavelengths used to scan the P and N regions are both 1060 nm, and the laser spot size is 400 μm × 400 μm. More specifically, the laser energy density used in the N region is 5 W / cm 2 The scanning speed is 45m / s, and the laser irradiation time is 10s; the laser energy density used in the P zone is 8W / cm 2 , the scanning speed is 45m / s, and the laser irradiation time is 8s.

[0142] Comparative Example 1 (HBC battery, Heterojunction Back Contact, heterojunction back contact battery)

[0143] The back contact solar cell with the same HBC structure as in Example 2 was placed in a tunnel light injection annealing device, where the heating temperature was set to 150°C to 210°C and the light injection intensity was set to 1 W / cm 2 ~3W / cm 2 The annealing time is 20s to 25s. More specifically, the heating temperature is set to 180°C and the light injection intensity is set to 2W / cm 2 The annealing time is 20s. The battery parameters tested after annealing and the battery parameters tested after annealing in Example 2 are shown in Table 1 below.

[0144] Table 1 Comparison of annealing effects of comparative example 1 and embodiment 2

[0145]

[0146] The present application method is compared with the traditional indiscriminate overall light injection annealing method. For example, compared with Example 1, Example 2 uses a laser selective local light injection annealing process. According to the differences in battery-related structures and materials, a customized process is performed, which has obvious advantages in reducing contact resistance, improving FF, and improving passivation effects.

[0147] In this specification, each embodiment is described in a progressive, parallel, or progressive and parallel manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0148] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for annealing a solar cell, characterized in that: A solar cell including two different sub-regions on the same surface, the solar cell including at least one first region and at least one second region located on the same surface, the first region and the second region are different, and the annealing method of the solar cell includes: The first region and the second region are irradiated with laser; wherein at least one of the laser parameters for irradiating at least a portion of the first region and the laser parameters for irradiating at least a portion of the second region is different, and the laser parameters include laser power density and laser irradiation time.

2. The annealing method of a solar cell according to claim 1, characterized in that: The first region and the second region correspond to a passivation contact region and a passivation non-contact region respectively; Alternatively, the first region and the second region correspond to two regions with opposite conductivity types.

3. The annealing method of a solar cell according to claim 1, characterized in that: The laser includes a first laser beam and a second laser beam. The first laser beam is first used to irradiate the first area, and then the second laser beam is used to irradiate the second area.

4. The annealing method of a solar cell according to claim 1, characterized in that: A first semiconductor layer is disposed in the first region, and a second semiconductor layer is disposed in the second region. The conductivity types of the first semiconductor layer and the second semiconductor layer are opposite. One of the first semiconductor layer and the second semiconductor layer includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding laser power density is 6 W / cm 2 ~9W / cm 2 The laser irradiation time is 5s to 10s, and the other semiconductor layer includes doped polysilicon, and the corresponding laser power density is 1W / cm 2 ~5W / cm 2 , laser irradiation time is 5s to 15s; Alternatively, one of the first semiconductor layer and the second semiconductor layer comprises doped amorphous silicon and / or microcrystalline silicon, and the corresponding laser power density is 5 W / cm 2 ~6W / cm 2 The laser irradiation time is 5s to 10s, and the other semiconductor layer includes doped polysilicon, and the corresponding laser power density is 5W / cm 2 ~6W / cm 2 , laser irradiation time is 11s~15s; Or, one of the semiconductor layers includes N-type doped polysilicon, and the corresponding laser power density is 1 W / cm 2 ~5W / cm 2 The laser irradiation time is 5s to 10s, and the other semiconductor layer includes a P-type silicon substrate, and the corresponding laser power density is 6W / cm 2 ~9W / cm 2 , laser irradiation time is 5s to 15s; Or, one of the semiconductor layers includes N-type doped polysilicon, and the corresponding laser power density is 4 W / cm 2 ~6W / cm 2 The laser irradiation time is 5s to 8s, and the other semiconductor layer includes a P-type silicon substrate, and the corresponding laser power density is 4W / cm 2 ~6W / cm 2 , laser irradiation time is 9s~15s; Or, one of the semiconductor layers includes doped polysilicon, and the corresponding laser power density is 2 W / cm 2 ~5W / cm 2 The laser irradiation time is 5s to 15s, and the other semiconductor layer includes a perovskite layer, and the corresponding laser power density is 0.5W / cm 2 ~1W / cm 2 , laser irradiation time is 10s~20s Or, one of the semiconductor layers includes doped polysilicon, and the corresponding laser power density is 1 W / cm 2 ~2W / cm 2 The laser irradiation time is 10 to 15 seconds, and the other semiconductor layer includes a perovskite layer, and the corresponding laser power density is 1W / cm 2 ~2W / cm 2 , the laser irradiation time is 16s~20s.

5. The annealing method of a solar cell according to claim 1, characterized in that: One of the first region and the second region includes doped polysilicon, and the corresponding laser power density is 1 W / cm 2 ~6W / cm 2 , laser irradiation time is 5s to 15s; Or, one of the first region and the second region includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding laser power density is 5 W / cm 2 ~9W / cm 2 , laser irradiation time is 5s~10s; Alternatively, when one of the first region and the second region only includes the doped silicon substrate and the passivation layer, the corresponding laser power density is 4 W / cm 2 ~9W / cm 2 , laser irradiation time is 5s to 15s; Or, one of the first region and the second region includes a perovskite layer, and the corresponding laser power density is 0.5 W / cm 2 ~2W / cm 2 , the laser irradiation time is 10s to 20s.

6. The annealing method of a solar cell according to claim 1, characterized in that: The first region is heated while the first region is irradiated with laser, and / or the second region is heated while the second region is irradiated with laser.

7. The annealing method of a solar cell according to claim 6, characterized in that: A first semiconductor layer is disposed in the first region, and a second semiconductor layer is disposed in the second region, and the conductivity types of the first semiconductor layer and the second semiconductor layer are opposite; one of the first semiconductor layer and the second semiconductor layer includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding heating temperature is 150° C. to 300° C., and the other semiconductor layer includes doped polycrystalline silicon, and the corresponding heating temperature is 200° C. to 300° C.; Or, one of the semiconductor layers includes N-type doped polysilicon, and the corresponding heating temperature is 200° C. to 300° C., and the other semiconductor layer includes a P-type silicon substrate, and the corresponding heating temperature is 200° C. to 300° C.; Alternatively, one of the semiconductor layers includes doped polysilicon, and the corresponding heating temperature is 200°C to 300°C, and the other semiconductor layer includes a perovskite layer, and the corresponding heating temperature is 100°C to 150°C.

8. The annealing method of a solar cell according to claim 6, characterized in that: One of the first region and the second region includes doped amorphous silicon and / or microcrystalline silicon, and the corresponding heating temperature is 150° C. to 300° C.; Or, one of the first region and the second region includes doped polysilicon, and the corresponding heating temperature is 200° C. to 300° C.; Or, when one of the first region and the second region only includes the doped silicon substrate and the passivation layer, the corresponding heating temperature is 200° C. to 300° C.; Alternatively, one of the first region and the second region includes a perovskite layer, and the corresponding heating temperature is 100° C. to 150° C.

9. The annealing method of a solar cell according to claim 6, characterized in that: The first region and the second region are heated by a heating surface, and the solar cell is placed on the heating surface, with the surface having the first region and the second region facing the heating surface; the heating surface includes at least one first heating zone and at least one second heating zone, and when laser irradiation is performed, the first heating zone is used to heat the first region, and the second heating zone is used to heat the second region.

10. The annealing method of a solar cell according to claim 9, characterized in that: The heating table comprises a first heating table and a second heating table located at two different positions, the first heating table comprises a plurality of first heating zones arranged at intervals, and the second heating table comprises a plurality of second heating zones arranged at intervals; The first region and the second region are heated separately. After the first region is annealed on the first heating stage, the solar cell is transferred to the second heating stage to anneal the second region.

11. The annealing method of a solar cell according to claim 1, characterized in that: The laser includes a first laser beam and a second laser beam. The first laser beam is used to irradiate the first area, and the second laser beam is used to irradiate the second area. The first laser beam and the second laser beam are both formed into multiple split beams through a beam splitter. The multiple split beams formed by splitting the first laser beam simultaneously irradiate multiple first areas with lasers, and the multiple split beams formed by splitting the second laser beam simultaneously irradiate multiple second areas with lasers.

12. The annealing method of a solar cell according to claim 1, characterized in that: The laser spot of the laser is a spliced ​​spot or a linear spot, the size of the spliced ​​spot is smaller than the size of the solar cell, the spliced ​​spot includes any one or more of a rectangular spot or a circular spot, and the length of the linear spot is greater than the size of the solar cell in the length or width direction.

13. The annealing method of a solar cell according to claim 1, characterized in that: The laser power density or the laser irradiation time of the laser irradiating the first region or the second region is 0.

14. An annealing device for a solar cell, characterized in that: The solar cell is annealed by the solar cell annealing method according to any one of claims 1 to 13.

15. An annealing device for a solar cell, characterized in that: include: A heating table, used for carrying and heating a solar cell having two different sub-regions on the same surface, wherein the solar cell comprises at least one first region and at least one second region located on the same surface, and the first region is different from the second region; A laser processing module is located above the heating table, and the laser processing module is used for the heating table to heat the solar cell while irradiating the first area and the second area with laser; wherein at least one of the laser parameters irradiating at least a portion of the first area is different from the laser parameters irradiating at least a portion of the second area, and the laser parameters include laser power density and laser irradiation time.

16. The annealing device for solar cells according to claim 15, characterized in that: The heating table includes a first heating zone and a second heating zone that are staggered or alternately arranged. When the solar cell is placed on the heating table, the first heating zone is used to heat the first area, and the second heating zone is used to heat the second area. Heating modules are arranged in the first heating zone and the second heating zone.

17. The annealing device for solar cells according to claim 16, characterized in that: The heating table top further includes a heat insulation area located between the adjacent first heating area and the second heating area, and a first heat insulation board is arranged in the heat insulation area.

18. The annealing device for solar cells according to claim 15, characterized in that: The heating table includes a first heating table and a second heating table that are independent of each other, the first heating table includes a plurality of first heating zones that are spaced apart, the second heating table includes a plurality of second heating zones that are spaced apart, the plurality of first heating zones and the plurality of second heating zones are arranged alternately, and the heating table also includes a first lifting mechanism connected to the first heating table and a second lifting mechanism connected to the second heating table.

19. An annealing device for a solar cell, characterized in that: include: A heating table, used for carrying and heating a solar cell including two different sub-areas on the same surface, wherein the solar cell includes at least one first area and at least one second area located on the same surface, and the first area is different from the second area; the heating table includes a first heating table and a second heating table located at a first station and a second station respectively, wherein the first heating table includes a plurality of first heating zones arranged at intervals, and the second heating table includes a plurality of second heating zones arranged at intervals; A cell handling module, the cell handling module is used to transfer the solar cell from one heating platform to another heating platform; A laser processing module is located above the heating table, and the laser processing module is used to heat the solar cell while irradiating the first area and the second area respectively with a first laser beam and a second laser beam; wherein at least one of the laser parameters irradiating at least a portion of the first area is different from the laser parameters irradiating at least a portion of the second area, and the laser parameters include laser power density and laser irradiation time; the laser processing module includes a first laser and a second laser respectively located above the first station and the second station, the first laser is used to emit the first laser beam, and the second laser is used to emit the second laser beam.

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