Method of passivating a plurality of solar cells disposed within a partially fabricated solar module

Abstract

Various embodiments provide a method of passivating a plurality of solar cells (12) disposed within a solar module (10) that is at least partially fabricated. The solar module includes a plurality of solar cells (12) and an electrical assembly that connects the plurality of solar cells into one or more strings of solar cells. The electrical assembly is connectable to an external circuit (42) that is external to the solar module. The method includes connecting the electrical assembly to an external circuit (42) that includes a current source (44) and using the current source to supply a forward current to the plurality of solar cells. The step of supplying the forward current is performed before lamination of the solar module or after lamination of the solar module. Some other embodiments provide a method of fabricating a solar module that is at least partially fabricated.

Description

Technical Field

[0001] This invention relates to a method for passivating multiple solar cells configured within a manufactured solar module. Background Technology

[0002] Solar modules used to provide electricity from sunlight typically include multiple solar cells (i.e., photovoltaic cells), each containing a semiconductor substrate. Specifically, each solar cell may typically include a polycrystalline silicon wafer that functions as a photoelectric conversion component.

[0003] Each solar module is typically manufactured by arranging multiple solar cells together in an array and then electrically connecting them to define a string. The solar cell strings are stacked between a top panel and a back panel, with an encapsulation inserted between them to protect the solar cells from moisture ingress. The stacked structure is mounted in a frame, and an external electrical connection is provided to allow power to be drawn from the solar cells.

[0004] The general goal of solar module development is to improve the power conversion efficiency of solar modules while balancing the need to reduce production costs. Efforts to achieve this goal have (in particular) focused on passivation defects, which are formed in the solar cells during their manufacturing process and persist throughout the construction of the solar module.

[0005] Known methods for passivating defects in solar cells are performed during or shortly after the manufacture of the solar cells. These methods are performed on individual solar cells and therefore must be carried out in a controlled environment to avoid damaging the solar cells.

[0006] Although such passivation methods can lead to improved device performance, there remains a persistent need to improve the passivation of solar cells and thereby improve the performance of solar modules. Summary of the Invention

[0007] In its broadest sense, the present invention provides a means of passivating multiple solar cells configured within at least partially manufactured solar modules, such that the resulting solar modules exhibit increased operating efficiency.

[0008] A first aspect of the invention provides a method for passivating a plurality of solar cells disposed within a solar module at least partially (e.g., partially) manufactured, wherein the solar module includes a plurality of solar cells and an electrical assembly connecting the plurality of solar cells together into one or more solar cell strings, wherein the electrical assembly is connectable to a circuit located outside the solar module. The method includes: connecting the electrical assembly to an external circuit including a current supply (e.g., a current supply unit or assembly); and using the current supply to supply a forward current to the plurality of solar cells; and wherein the step of supplying the forward current is performed before or after the stacking of the solar module.

[0009] The supplied forward current is transmitted through each of the plurality of solar cells arranged in the solar cell string, causing passivation of defects in the solar cells. Defect passivation leads to an increase in the open-circuit voltage (Voc) and fill factor (FF) of the solar cells, thereby improving the performance of the solar module during use.

[0010] The supplied forward current can also passivate defects within the electrical assembly. For example, by passivating defects at the interface between two components of the electrical assembly (e.g., two conductive components) and / or between the electrical assembly and one of multiple solar cells. This increases the extraction of charge through the electrical assembly, thereby further improving the performance of the solar module.

[0011] The method according to the present invention enables multiple solar cells to be passivated simultaneously using a single current supply (e.g., a voltage source). Advantageously, the passivation step is performed before or after the stacking of the solar cells (i.e., not simultaneously with the stacking process), because when performed at lower temperatures and / or pressures than those present during stacking, the passivation step produces greater defect removal and thus an increase in efficiency.

[0012] This method also conveniently utilizes existing electrical connections within the solar module (i.e., the solar module electrical assembly) to achieve passivation treatment on the solar cells. This eliminates the need for additional electrical connection equipment. Simultaneously, the outer casing of the solar module provides a protective environment for multiple solar cells during passivation treatment, allowing the method to be performed in various locations (e.g., in a separate location relative to the solar module manufacturing facility). Therefore, this method increases the efficiency and throughput of the solar module manufacturing process.

[0013] When a solar cell operates under dark conditions (e.g., when no light is incident on the solar cell), the forward current in the solar cell corresponds to the flow of charge carriers through the solar cell in the direction permitted by the built-in photodiode (e.g., which may be formed at the interface between p-type and n-type materials). A forward bias can be applied across the solar cell to generate the forward current. Under this forward current condition, negative charge carriers (e.g., electrons) flow to the positive terminal (e.g., the positive electrode) of the solar cell, while positive charge carriers (e.g., holes) flow to the negative terminal (e.g., the positive electrode). Therefore, the forward current defines the positive current of the solar cell.

[0014] If a reverse bias is applied to the solar cell, a reverse current is obtained, which corresponds to the charge carrier flow through the solar cell in a direction not permitted by the built-in photodiode. Therefore, only a very small reverse current is obtained under such reverse bias and reverse current conditions.

[0015] When the solar cell operates under normal lighting conditions (e.g., when light is incident on the solar cell), it is configured to operate using a negative photocurrent caused by the absorption of photons. A load is applied to the solar cell to generate electricity, as will be understood by those skilled in the art.

[0016] As described above, the method of the present invention supplies forward current to the solar cell. This forward current (e.g., positive current) has the opposite polarity (e.g., negative photocurrent) to the normal operating current of the solar cell. In this way, the method of the present invention can be defined as operating the solar cell using a "reverse" current (e.g., forward current) that is in the "opposite" direction to the current experienced during its normal operation.

[0017] The selective features will now be explained. These can be applied individually or in combination with any aspect.

[0018] The stack of solar modules may include applying heat and / or (negative) pressure to the solar cell modules, which are contained in a capsule inserted between the front and back sheets of the solar module. This heat and / or (negative) pressure may be a sufficient quantity to bond the solar cell strings, the capsule, and the front and back sheets together (e.g., a temperature greater than or equal to the melting temperature of the capsule (typically 90°C to 160°C) and / or a pressure less than or equal to -10 kPa (i.e., a vacuum) (e.g., less than -10 kPa and greater than -95 kPa) or greater than or equal to 10 kPa (e.g., greater than 10 kPa and at most 95 kPa)).

[0019] By performing the step of supplying forward current before or after the stacking of solar modules, this method step can be omitted during the stacking of solar modules (e.g., omitted during the application of heat and / or pressure to achieve the stacking).

[0020] This method step can be implemented before applying heat from an external heat source to the solar cell string by performing a step of supplying forward current before the solar module is stacked.

[0021] This method step can be performed before applying stacking pressure to the solar cell string, for example, before applying (negative) pressure to the solar cell string, by performing a step of supplying forward current before the stacking of the solar module.

[0022] The method involves performing a forward current supply step before the solar module is stacked. This step can be performed before the solar cell string is inserted between one or more of the front sheet, back sheet, upper encapsulation layer, and lower encapsulation layer of the solar module.

[0023] This method involves performing a forward current supply step before the solar cell strings are positioned in a pressure chamber or compressor, by performing the forward current supply step before the solar modules are stacked.

[0024] By performing the step of supplying forward current before stacking the solar modules, this method step can be performed immediately after the step of electrically connecting at least two of the multiple solar cells together to form a series (i.e., there are no intermediate steps between the step of electrically connecting the solar cells together and the step of connecting the electrical assembly to an external circuit containing a current supply and subsequently using the current supply to supply forward current to the multiple solar cells).

[0025] By performing the step of supplying forward current after the stacking of solar modules, this method step can be performed after the step of allowing heat from the stack of at least partially manufactured solar modules to dissipate at least partially (e.g., the steps of connecting the electrical assembly to an external circuit and supplying forward current can be performed before any further manufacturing steps are performed after the stacking of solar modules).

[0026] By performing the step of supplying forward current after the stacking of solar modules, this method step can be performed after the step of releasing the stacking pressure applied to at least partially manufactured solar modules, for example, after releasing vacuum pressure.

[0027] By performing the step of supplying forward current after the stacking of solar modules, this method step can be performed after the step of allowing the encapsulation layer of the solar module, which is at least partially manufactured, to solidify (e.g., after the temperature of the encapsulation layer has been reduced to below the melting temperature of the encapsulation, for example, less than or equal to 120°C, less than or equal to 110°C, less than or equal to 100°C, less than or equal to 90°C, or less than or equal to 80°C).

[0028] This method involves performing a forward current supply step after the solar module is stacked, which can be done after the junction box and / or junction cable are connected to the solar cell.

[0029] The method described above for passivating multiple solar cells configured within at least part of a manufactured solar module may be referred to herein (and throughout this specification) as a passivation method. The passivation method can be implemented when the solar module is under illumination (e.g., under bright conditions when radiation is incident on the solar cells) and under non-illumination conditions (e.g., under dark conditions when substantially no radiation is incident on the solar cells). Examples of operating the solar cells under dark conditions may involve operating the solar cells in a dark room or when the solar cells are substantially (e.g., completely) shielded from any incident light. When the passivation method is implemented in an illuminated solar module, a forward bias applied to the solar cells is sufficient to overcome a negative photocurrent (which would otherwise be generated by illumination) and generates a positive current through the solar module.

[0030] It will be understood that each solar cell includes a junction between two components configured to separate charge carriers for light generation. This junction can be formed between two semiconductor materials. For example, a junction formed between a positively doped (p-type) semiconductor material and a negatively doped (n-type) material (e.g., to form a pn junction). Forward-biased solar cells may involve applying a positive voltage to the p-type material and a negative voltage to the n-type material to establish an electric field across the junction. The electric field generated by the forward bias acts to reduce the built-in electric field formed by the junction (e.g., the potential barrier associated with the depletion region formed between the pn materials). Conversely, the application of a reverse bias increases the built-in electric field at the junction. When a bias is applied to a solar cell under normal conditions (e.g., room temperature), if the applied voltage is large enough to overcome the junction barrier potential (e.g., about 0.7 volts for a crystalline silicon solar cell), only a current is established across the junction. The resulting current corresponds to the diffusion of charge carriers across the junction.

[0031] The forward current supplied to the solar module can be achieved by applying a potential difference (such as voltage or bias) to the electrical assembly. The voltage applied to the electrical assembly causes the injection of forward current into the electrical assembly, thereby supplying multiple solar cells.

[0032] The current supply may include a controllable charge carrier injector. The controllable charge carrier injector can be configured to inject charge carriers into the electrical assembly of the solar module and can respond to control signals received from a controller, which can be operated by a user of the current supply. The current supply may include a voltage source. The method may include the step of configuring the current supply to supply forward current to multiple solar cells. This step may include configuring the voltage source to apply a forward bias to the electrical assembly to supply forward current to the multiple solar cells. In this manner, the voltage source can be configured to supply a load current that is injected into the electrical assembly of the solar module.

[0033] The current supply can be configured to supply forward current to multiple solar cells under forward bias conditions (e.g., by applying forward bias to the electrical assembly of the solar module).

[0034] The voltage applied to the electrical assembly can be defined as the passivation voltage of the passivation method. Therefore, the forward current injected into multiple solar cells can define the passivation current of the passivation method. Meanwhile, the passivation method is characterized by applying a bias voltage to the electrical assembly for a given period of time, which can define the passivation period of the passivation method.

[0035] It will be understood that the method according to the present invention involves passivating a plurality of solar cells after they have been at least partially assembled (e.g., at least partially installed) within a solar module.

[0036] A solar module, at least partially manufactured, may include multiple solar cells disposed within an outer casing of the solar module. The solar module may be a multilayer solar module when the solar cells are disposed within the outer casing. Circuitry may be external to the outer casing of the solar module. This method enables the solar cells to be passivated simultaneously with their in-situ placement within the solar module. By passivating the solar cells after they have been installed in the solar module, this method eliminates the need for separately passivating the solar cells (e.g., before they are manufactured into the solar module).

[0037] Multiple solar cells can be configured within the stacked structure of a solar module (i.e., within the outer casing of the solar module). For example, the casing may include a front sheet and a back sheet, with multiple solar cells inserted therebetween. Therefore, the passivation method can be performed substantially after the solar cells are configured (e.g., mounted) within the stacked structure of the solar module.

[0038] The outer casing of a solar module, at least partially manufactured, may include a front sheet and a back sheet. An encapsulation may be inserted with multiple solar cells between the front and back sheets of the casing. The encapsulation may be heated to bond the multiple solar cells and the casing together to form a solar module at least partially manufactured, as will be understood by those skilled in the art. A method of manufacturing a solar module at least partially manufactured may include inserting the encapsulation and multiple solar cells between the front and back sheets, and then heating the solar module (e.g., the encapsulation) to bond the solar cells to the casing (e.g., between the front and back sheets to form a stacked structure). When the step of supplying forward current is performed after the stacking of the solar module, the method of passivating the multiple solar cells may further include allowing heat from the at least partially manufactured solar module to dissipate at least partially from the multiple solar cells before supplying forward current to the multiple solar cells.

[0039] Based on the example configuration, it will be understood that a solar module at least partially manufactured can be defined as a module that does not require further heating method steps to complete the manufacturing process. Therefore, substantially all manufacturing steps involving heat can be completed before the start of the passivation process. In other embodiments, a solar module at least partially manufactured can be defined as a module in which the only further heating method step required to complete the manufacturing process is soldering one or more diodes of the electrical assembly to the module / stack. In other embodiments, a solar module at least partially manufactured can be defined as a module in which electrical connections between solar cells and selectively between multiple strings (if present) have been formed.

[0040] The method according to the present invention may include supplying forward current to multiple solar cells (e.g., applying voltage or bias to an electrical assembly) based on whether the temperature of multiple solar cells is at or below a predetermined temperature. The method may include determining the temperature of the multiple solar cells, and if the temperature is below the predetermined temperature, supplying forward current only to the multiple solar cells. In this manner, the method may include waiting for heat from the solar module manufacturing process (at least partially) to dissipate before passivating the multiple solar cells. In one embodiment, the method may involve cooling the solar module to reduce the amount of time between the completion of the heating step and the start of the passivation step. For example, the cooling process may involve passive cooling components (such as a heat sink) and / or active cooling components (such as a fan for guiding airflow above the surface of the module).

[0041] The inventors have discovered that the method according to the present invention can achieve increased passivation of multiple solar cells when the method begins with the solar cells at ambient temperature (e.g., room temperature, such as 20°C + / - 5°C). For example, passivation can advantageously be performed when the solar cells are not heated by an external source and / or when the solar cells do not retain the heat energy previously absorbed during the manufacture of the solar module. However, the passivation method can still achieve increased passivation of multiple solar cells when the method is implemented with the solar cells at an ambient temperature above (compared to not implementing the passivation method). In particular, initiating current injection when the solar cells are not heated and / or when the solar cells do not retain the heat energy previously absorbed during the manufacture of the solar module (e.g., when the solar cells are at room temperature) is particularly advantageous in cases where the solar cells are heterojunction (HJT) solar cells.

[0042] The method may include allowing heat that may accumulate during the module manufacturing process to dissipate between the supply of forward current to the solar cells. Conversely, it has been determined that if the passivation treatment is applied immediately (e.g., immediately) after the solar cells are stacked within the solar module (e.g., while the solar cells are still hot), the effectiveness of the passivation method may be reduced compared to if the passivation method is implemented once the heat has been dissipated from the module.

[0043] The process of determining the temperature of multiple solar cells may include measuring the temperature of the solar cells. For example, an infrared sensor or a non-contact thermometer may be used to directly measure the temperature of at least one of the solar cells in order to determine when forward current should be supplied, as will be easily understood by those skilled in the art.

[0044] Instead of measuring the temperature, the method may include measuring how much time has elapsed since the manufacture of the solar module was completed (e.g., after the solar cells have been installed in the outer casing of the solar module and the casing is joined together, and / or after the external heat source attached to the solar cells has been removed). Once the measured time exceeds a known time value indicating how long it would take for the temperature of the solar module to drop to a predetermined temperature, a forward bias may be applied.

[0045] In an exemplary configuration, the method may include determining that the temperature of the solar cell is near room temperature (e.g., near 20°C) before supplying forward current to the power assembly.

[0046] This method may include applying a voltage such that the magnitude (or absolute value) of the forward current supplied to (e.g., injected into) the electrical system is equal to or greater than the rated current (Impp) of at least one of the solar cells of the solar module (i.e., the current passing through at least one of the solar cells when the power output from the solar cell is at its maximum). In a further example, the magnitude of the forward current supplied to the electrical system is greater than or equal to the rated current of the solar module (i.e., the current at the maximum power point). For example, the rated current of the solar module may be as high as -10 amps (selectively as high as -10.5 amps), such that the magnitude of the rated current of the solar module is as high as 10 amps (selectively as high as 10.5 amps). In the case of a rated current of -10 amps, the forward current supplied to the electrical system may be at least +10 amps. Therefore, the magnitude of the forward current is at least 10 amps, such that the magnitude of the passivation current is greater than or equal to the magnitude of the rated current of the solar cell (i.e., 10 equals 10). In another example, the forward current supplied to the power assembly can be +12 amps when the rated current is -10 amps. Therefore, the passivation current is greater than the rated current (i.e., 12 is greater than 10).

[0047] The method may include applying a voltage such that the magnitude of the forward current supplied to the electrical assembly is greater than or equal to the magnitude of the short-circuit current of at least one of the solar cells of the solar module, or the magnitude of the short-circuit current of the solar module. The short-circuit current defines a current value that is the maximum current that the solar cell or module (e.g., the electrical assembly and / or multiple solar cells) is designed to conduct during normal operation. In this manner, the voltage generates a forward current whose magnitude is greater than or equal to the magnitude of the short-circuit current of at least one of the solar cells of the module, or greater than or equal to the magnitude of the short-circuit current of the solar module.

[0048] The method may include determining the short-circuit current of the solar module and applying a forward voltage to the electrical assembly to inject a forward current greater than the short-circuit current into multiple solar cells.

[0049] The forward current supplied to the power assembly may be equal to or greater than the short-circuit current of the solar module (e.g., at least 10.5 amps). Alternatively, the method may include injecting a forward current into multiple solar cells, the forward current being at least (or approximately) 314% (e.g., 33 amps) of the short-circuit current of the solar module. The method may include injecting a forward current that is at least (or approximately) 419% (e.g., 44 amps) of the short-circuit current of the solar module. The method may include injecting a forward current that is at least (or approximately) 476% (e.g., 50 amps) of the short-circuit current of the solar module. The method may include injecting a forward current that is at least (or up to) 666% (e.g., 70 amps) of the short-circuit current of the solar module.

[0050] The method may include supplying a forward current to the electrical assembly for a predetermined passivation period (e.g., a passivation cycle). The method may include supplying the forward current to the electrical assembly for at least 120 minutes (e.g., approximately 120 minutes or two hours). It has been determined that a passivation treatment of approximately two hours produces the best passivation effect. Alternatively, the method may include supplying the forward current to the electrical assembly for at least one minute (e.g., approximately 1 minute), at least five minutes (e.g., approximately 5 minutes), at least 10 minutes (e.g., approximately 10 minutes), at least fifteen minutes (e.g., approximately 15 minutes), at least thirty minutes (e.g., approximately 30 minutes), or at least sixty minutes (e.g., approximately 60 minutes).

[0051] This method may involve supplying forward current to the electrical assembly for up to 120 minutes (e.g., up to two hours), or approximately 120 minutes. By limiting the duration of the passivation treatment to up to 120 minutes, this advantageously balances the need to optimize the power output of the solar module with the need for time-efficient processing of the solar module.

[0052] A preferred embodiment of the present invention may involve applying voltage to the electrical assembly to inject a forward current of approximately 314% of the short-circuit current over a period of up to two hours. For the resulting bifacial solar module, an increase in power output of 2.9W can be achieved compared to a comparable solar module that has not undergone passivation. This increase in output from the bifacial solar module corresponds to a 2.35% increase in power compared to an untreated solar module.

[0053] The exemplary configuration of the present invention can provide a passivated solar module according to any of the previously described.

[0054] A solar module may be a crystalline silicon solar cell module. It will be understood that the crystalline silicon solar cell module defines a solar module in which at least one (or each) of a plurality of solar cells comprises a crystalline silicon substrate that functions as a photoelectric conversion component. The solar module may include a plurality of solar cells arranged in an array. In this way, the solar cells may be arranged in a sequential sequence extending across a horizontal plane of the solar module. The array of solar cells may extend in a first direction and a second direction perpendicular to the first direction.

[0055] Multiple solar cells can be arranged in substantially the same plane. Therefore, solar cells can be arranged in a substantially planar array. Each solar cell can be arranged such that it is aligned within the same reference plane. For example, a first solar cell of a plurality of solar cells can be arranged (e.g., oriented) such that the horizontal plane of the first solar cell is aligned with the horizontal plane of a second solar cell. The reference planes of the first and second solar cells can be substantially aligned (e.g., parallel) with the horizontal plane of the solar module.

[0056] A solar module may include width, length, and height. The solar module may have a thickness, measured in the height direction, which is substantially smaller than its length and width. An array of solar cells may be configured in an array extending in the longitudinal (e.g., vertical) and / or lateral (e.g., horizontal) directions of the solar module. In embodiments, the solar cells may be configured in a grid form, such as a rectangular or square grid.

[0057] Multiple solar cells may each include a first and a second surface. The first surface may be configured to face a radiation source (e.g., the sun) when the solar module is in use. The second surface may be configured opposite to the first surface. The first surface of each of the first and second solar cells may define a front (e.g., foremost) surface. The second surface of each of the first and second solar cells may define a back (e.g., last) surface, such that the front surface is opposite to the back surface.

[0058] Each of the first and second solar cells can be configured with a length, a width, and a height. The height (i.e., thickness) of each solar cell can be less than its respective length and width. The length of each solar cell can be less than its respective width. The barrier film can be configured to extend across the entire length and width of each solar cell.

[0059] One or more of a number of solar cells (e.g., all of them) may be HJT solar cells.

[0060] The housing may include a front sheet or front panel disposed on the front side of the solar module. The housing may also include a back sheet or back panel disposed on the back side of the solar module. At least one or both of the front and rear sheets may be formed of glass. At least one (or both) of the front and rear sheets may be transparent. The back sheet may be reflective. The back sheet may be configured with a reflective surface such that it reflects unabsorbed light back toward the solar cell. That is, the housing may be suitable for bifacial or single-sided solar cells.

[0061] The housing may include a frame, or one or more frame assemblies. The frame may be configured to hold and position the components of the solar module and provide a seal around the perimeter of the housing assemblies (e.g., front and back sheets). In embodiments in which the solar module includes a front and back sheet, the frame may apply a compressive force between the front and back sheets to hold the components of the solar module in position, as will be readily understood by those skilled in the art.

[0062] In an embodiment, the solar module may include an encapsulation layer or a film. Multiple solar cells may be sandwiched (e.g., inserted) between a front encapsulation and a rear encapsulation. The front and rear encapsulations may be sandwiched between a front sheet and a back sheet. The encapsulations (or each) may be configured to extend in a first and second direction of the solar module to overlap multiple solar cells. The encapsulations may extend in a longitudinal (i.e., longitudinal) direction from a side end of the solar module to an opposite side end of the solar module. The encapsulations may extend in a transverse (e.g., transverse) direction from a longitudinal end of the solar module to an opposite longitudinal end of the solar module. The front and back encapsulations may be formed of the same material (e.g., EVA). The front and back barrier films may be formed of the same material (e.g., TPO).

[0063] The electrical assembly may include at least one conductive component (e.g., a conductive element) configured to electrically connect a first solar cell of a plurality of solar cells to a second solar cell of a plurality of solar cells. The electrical assembly may include conductive components in the form of interconnects (e.g., connectors) configured to connect between electrodes (e.g., printed or plated electrodes, such as printed or plated busbars) disposed on the surface of the solar cells. The at least one conductive component may define a foil electrode assembly, as explained in more detail below. In this way, the electrical assembly of the solar module is configured to provide electrical connections between a plurality of solar cells in the solar module.

[0064] Electrical connections within a solar module (e.g., provided by at least one conductive component) can be configured to withstand at least forty-five amperes of applied forward current. Typically, the junction box and / or junction cables of the electrical assembly are limiting factors for the forward current that can be applied to the solar module.

[0065] An electrical assembly can be configured to electrically connect at least two of a plurality of solar cells together to form a string. Solar cells within this string can be connected in series. A solar module can contain multiple solar cell strings. Solar cell strings can be electrically connected via an electrical assembly (e.g., via conductive components of the electrical assembly). Solar cell strings can be connected in parallel.

[0066] The electrical assembly can be configured to form an electrical connection between a plurality of solar cells disposed within a solar module and circuitry disposed outside the solar module. In an embodiment, the electrical assembly can be configured to provide an electrical connection between two solar modules. The electrical assembly may include at least one external connector that physically extends from inside the solar module (e.g., from inside the housing) to outside the solar module (e.g., to the outside of the housing). The external connector may be through an opening in the outer housing of the solar module or terminated (e.g., an opening in the backsheet of the housing). The external connector may be connectable to circuitry, as will be understood by those skilled in the art.

[0067] The electrical assembly may include at least one junction box disposed on the outer surface of the solar module (e.g., positioned on the outer surface of the housing). The junction box may be disposed on the back surface of the solar module (e.g., on the back surface of the backsheet). The junction box may be substantially disposed close to (e.g., adjacent to) an opening in the housing through which the external connector exits the solar module. The junction box may be configured to substantially cover (e.g., seal) the opening in the housing to prevent moisture from entering the housing through the opening.

[0068] The junction box can be configured to house at least one connection point of the electrical assembly, whose enabling solar module is detachably connected to another solar module and / or to external circuitry. This at least one connection point defines a plug-and-receptacle connection between the electrical assembly's external connector and external circuitry, as will be readily apparent to those skilled in the art. The electrical connector may include a junction cable extending away from the junction box, providing a mechanism for connecting the solar module to an external device, such as another solar module.

[0069] The junction box may contain (e.g., house) one or more electronic components of an electrical assembly. For example, the electrical assembly may contain one or more diodes that control the flow of electricity to multiple solar cells (e.g., in cases where some solar cells are partially shaded). The electrical assembly may contain a fuse assembly (e.g., a fuse) configured to provide overcurrent protection to the solar cells. The fuse assembly may be calibrated to an overcurrent value of twenty-five amperes. The junction box may be filled (e.g., at least partially filled) with a sealant to prevent moisture from entering the junction box and / or the interior of the solar module.

[0070] The junction box of the electrical assembly can be configured to withstand at least 45 amperes of the applied forward current.

[0071] According to an exemplary configuration, a system for passivating multiple solar cells configured within at least partially manufactured solar modules can be provided, wherein the manufactured solar module includes: multiple solar cells, and an electrical assembly connecting the multiple solar cells together to form one or more solar cell strings, wherein the electrical assembly is connectable to a circuit located outside the solar module. The system includes: an external circuit connectable to the electrical assembly of the solar module, wherein the external circuit includes a current supply. The current supply is configured to supply forward current to the multiple solar cells, either before or after the stacking of the solar module.

[0072] The external circuit may include multiple conductive wires or cables that can be connected to the electrical assembly of the solar module. The circuit may be located outside the outer casing of the solar module.

[0073] A solar module, at least in part, may contain multiple solar cells configured within an outer casing of the solar module.

[0074] The current supply may include a voltage source configured to supply (e.g., inject) current into the electrical system of the solar module. The voltage source may include a power converter (e.g., a direct current (DC) power supply unit) that can be connected to an alternating current (AC) grid. Alternatively, the voltage source may include a battery. The voltage source may include a controller or control unit configured to control the output of the voltage source. The voltage source may include positive and negative terminals for connection to a circuit, as will be understood by those skilled in the art.

[0075] In the preceding paragraphs, any reference to "solar cell" may be understood to refer to at least one of a plurality of solar cells. A solar cell may comprise a plurality of components, each comprising a semiconductor material (e.g., a semiconductor layer). The plurality of components may define a layered structure of the solar cell. At least one or all of the plurality of components may be configured to determine a conductivity type (e.g., p-type or n-type). In some cases, the semiconductor material may be undoped (e.g., using an intrinsically passivated layer).

[0076] The layered structure may include a semiconductor substrate, which may be formed of crystalline silicon (e.g., a single-crystal silicon wafer). The substrate may be configured with a first conductivity type (e.g., n-type), and the layered structure may include a collector layer configured with a second conductivity type opposite to the first conductivity type (e.g., p-type), thus forming a pn junction with the substrate. According to this configuration, the collector layer may define a minority charge carrier collector layer (e.g., a hole-collector layer) for the solar cell.

[0077] During the operation of a solar cell, multiple electron-hole pairs are generated by light incident on the substrate. When the substrate is n-type and a few charge carrier collector layers are p-type (e.g., hole-collector layers), the separated holes and electrons move separately to the p-type hole-collector layer and the n-type substrate. Therefore, hole operation is the dominant charge carrier in the p-type hole-collector layer, while electron operation is the dominant charge carrier in the n-type substrate.

[0078] Depending on the alternative configuration, the substrate can be p-type and the minority charge carrier collector layer can be n-type (e.g., an electron-collector layer), thus forming a pn junction with the substrate. In this example, the separated electrons and holes move separately to the n-type electron-collector layer and the p-type substrate.

[0079] The collector layer defines a primary charge carrier collector layer, configured with a first conductivity type (e.g., n-type), which is the same as the conductivity type of the substrate. For example, both the substrate and the primary charge carrier collector layer can be n-type, such that the primary charge carrier collector layer defines an electron-collector layer. In this way, the primary charge carrier collector layer can be configured to selectively filter (or extract) charge carriers from the substrate. Therefore, when the solar cell is in use, electrons generated by light incident on the substrate can be collected in the electron-collector layer, where these electrons operate as primary charge carriers.

[0080] A first collector layer may be disposed on a first surface of the substrate. The layered structure of the solar cell may further include a second collector layer (e.g., a back field layer) disposed on a second surface of the substrate opposite to the first surface. Alternatively, both the first and second collector layers may be disposed on the same surface of the substrate, for example, on the second (back) surface of the substrate (e.g., in the case of a cross-joined back contact solar cell). The first and second surfaces may respectively define the front and back surfaces of the substrate. The layered structure of the solar cell may further include a passivation layer disposed between the substrate and the respective first and second collector layers; or, when both the first and second collector layers are provided on the same surface of the substrate (e.g., the second surface), the passivation layer may be disposed on an opposite surface (e.g., the first surface).

[0081] According to the example configuration, the substrate can be formed from an n-type monocrystalline silicon wafer, which exhibits a longer minority carrier lifetime compared to a p-type monocrystalline silicon wafer. The first collector layer (e.g., the front collector layer) may comprise an amorphous material (e.g., amorphous silicon) that is at least partially doped to be p-type. The second collector layer (e.g., the back collector layer) may comprise an amorphous material (e.g., amorphous silicon) that is at least partially doped to be n-type. Alternatively, the first collector layer (e.g., the front collector layer) may comprise an amorphous material (e.g., amorphous silicon) that is at least partially doped to be n-type, while the second collector layer (e.g., the back collector layer) may comprise an amorphous material (e.g., amorphous silicon) that is at least partially doped to be p-type.

[0082] This configuration can contribute to the formation of heterojunction technology (HJT) type solar cells, which are defined as such because the solar cell combines two different materials to create a charge-separated pn junction. Alternatively, the solar cell may comprise a multi-junction (e.g., tandem) solar cell, which is defined as such because the solar cell includes two or more charge-separated junctions and two or more charge-generating photon-absorbing layers.

[0083] A solar cell may include an electrode configured to extract charge carriers generated by light from the solar cell, opposite to the layered structure. The electrode may be configured such that a collector layer is inserted between the electrode and the substrate.

[0084] When the collector layer is disposed on the back (last) surface of the substrate, electrodes can be disposed on the back surface of the layered structure to define the back electrode of the solar cell. When the collector layer is disposed on the front (first) surface of the substrate, electrodes can be disposed on the front surface of the layered structure to define the front electrode of the solar cell. The solar cell may include a positive electrode (disposed on the same surface of a layered structure such as a p-type collector layer) and a negative electrode (disposed on the same surface of a layered structure such as an n-type collector layer). Each electrode may be configured to form an ohmic contact with the surface of the respective collector layer.

[0085] Each of the positive and negative electrodes may comprise a plurality of finger electrodes disposed on the surface of a respective collector layer of the solar cell, as will be readily apparent to those skilled in the art. The finger electrodes within each of the plurality of positive and / or negative finger electrodes may extend in a lateral direction parallel to the width direction of the solar cell. These finger electrodes in the plurality may be substantially parallel to each other. Therefore, the plurality of finger electrodes may form an array of parallel, longitudinally spaced (e.g., equally spaced) finger electrodes. Similarly, the plurality of positive finger electrodes may form an array of parallel, longitudinally spaced (e.g., equally spaced) finger electrodes.

[0086] The positive and / or negative electrodes may include one or more conductive components (e.g., extension buses) disposed on top of the finger electrodes. The conductive components may extend in a longitudinal direction parallel to the length of the solar cell (e.g., perpendicular to the finger electrodes). In this manner, multiple finger electrodes can be inserted between one or more extension buses and the substrate. The multiple extension buses and finger electrodes may each be formed of a conductive material, enabling the flow of charge carriers from the surface of the solar cell to external circuitry. In this way, each of the buses and finger electrodes defines a current collector for the electrode.

[0087] One or more extension buses can be configured to form an electrical connection between the finger electrodes and the electrical assembly of the solar module. Multiple buses of one solar cell can be electrically coupled to multiple buses of a second solar cell via at least one interconnect (e.g., with a connector), as will be readily apparent to those skilled in the art. Thus, at least one interconnect defines at least a portion of the electrical assembly of the solar module.

[0088] Alternatively, instead of connections via connectors, solar cells can be connected via foil wire connectors, as will be understood by those skilled in the art. The foil wire connectors can form the electrical assembly of a solar module. Each foil wire connector may include conductive components (e.g., wires, or wire portions) that form part of the electrical assembly of the solar module. A first plurality of conductive wire portions may be disposed on a first surface of a first solar cell. The first plurality of conductive wire portions may be electrically coupled to a second plurality of conductive wire portions disposed on a second surface of a second solar cell. In one embodiment, the first plurality of conductive wire portions may be integrated with the second plurality of conductive wire portions.

[0089] In the case of foil-wire connectors, at least one (or each) of a plurality of conductive components may be disposed in and / or on a film. The film may be configured to be insulating and / or optically transparent. The film may be configured to provide adhesion between the solar cell and the conductive components, such that the conductive components are properly spaced on the solar cell. In this manner, the film enables the conductive components to be properly aligned with the solar cell. The film may provide a mechanical connection between the conductive components and the solar cell.

[0090] According to the exemplary configuration, each of the plurality of solar cells may include a layered structure comprising an n-type substrate, a p-type hole collector (or hole collector layer) disposed on the rear surface of the substrate, and an n-type electron collector (or electron collector layer) disposed on the front surface of the substrate (e.g., opposite to the p-type hole collector). The hole collector may be electrically connected to the positive electrode, configured such that the hole collector is disposed between the positive electrode and the substrate. The electron collector may be electrically connected to the negative electrode, configured such that the electron collector is disposed between the negative electrode and the substrate.

[0091] A second aspect of the invention provides a method for at least partially manufacturing a solar module, wherein the method comprises: connecting a plurality of solar cells to an electrical assembly such that the plurality of solar cells are connected together in one or more strings, the electrical assembly being connectable to a circuit located outside the solar module; and passivating the plurality of solar cells disposed within the at least partially manufactured solar module in accordance with any of the foregoing description.

[0092] The method may further include stacking the solar module; and the step of supplying forward current as part of passivating the plurality of solar cells may be performed before or after the step of stacking the solar module.

[0093] This step in the tandem solar module may include applying heat (and / or (negative) pressure) to the solar cell module, which comprises the solar cell strings contained in an encapsulation inserted between the front and back sheets of the solar module. The heat and / or (negative) pressure may be a sufficient quantity to bond the solar cell strings, the encapsulation, and the front and back sheets together (e.g., a temperature greater than or equal to the melting temperature of the encapsulation (typically 90°C to 160°C) and / or a pressure less than or equal to -10 kPa (i.e., a vacuum) (e.g., less than -10 kPa and greater than -95 kPa) or greater than or equal to 10 kPa (e.g., greater than 10 kPa and at most 95 kPa)).

[0094] The method of at least partially manufacturing a solar module may further include configuring multiple solar cells within an outer casing of the solar module.

[0095] In cases where the method involves configuring multiple solar cells within an outer casing of a solar module, the method of at least partially manufacturing the solar module (e.g., a solar module manufacturing process) may further include applying heat (and / or (negative) pressure) toward the casing to bond the solar cells within the solar module (e.g., a stacking process). The method may include allowing heat from the solar module manufacturing process to be at least partially dissipated from the multiple solar cells before supplying forward current to the multiple solar cells.

[0096] For example, the housing may include a front sheet and a back sheet. In this case, a method of at least partially manufacturing a solar module may include inserting an encapsulation of the solar module and a plurality of solar cells between the front and back sheets of the housing; and heating the encapsulation to engage the solar cells within the housing. A method of passivating the plurality of solar cells may include allowing heat from the heating of the encapsulation to be at least partially dissipated from the plurality of solar cells before supplying forward current to the plurality of solar cells.

[0097] It will be understood that the terms “conductive” and “insulating” as used herein are explicitly intended to refer to electrical conduction and electrical insulation, respectively. The meaning of these terms will be particularly apparent in light of the technical context of this disclosure (i.e., photovoltaic solar cell devices). It will also be understood that the term “ohmic contact” is intended to refer to a non-rectifying electrical junction (i.e., a junction between two conductors exhibiting substantially linear current-voltage (IV) characteristics).

[0098] Those skilled in the art will understand that, in addition to mutual exclusions, the features or parameters described with respect to any of the above-described states can be applied to any other state. Furthermore, in addition to mutual exclusions, any feature or parameter described herein can be applied to any state and / or combined with any other feature or parameter described herein. Attached Figure Description

[0099] Various aspects and embodiments of the invention will now be described by way of example and with reference to the accompanying drawings.

[0100] Figure 1 and Figure 2 Each solar module containing multiple solar cells is shown in plan and cross-sectional side views.

[0101] Figure 3 Displays the passivation configuration in Figure 1 A system of multiple solar cells in a solar module.

[0102] Figure 4 The flowchart illustrates the passivation configuration. Figure 1 A method for using multiple solar cells in a solar module.

[0103] Figure 5 This is a current-voltage curve for solar modules that operate in both dark and lit conditions.

[0104] Figures 6 to 10 Showing already experienced Figure 4 Performance data of solar modules using passivation methods. Detailed Implementation

[0105] The features and embodiments of this disclosure will now be discussed with reference to the accompanying drawings. Further features and embodiments will be apparent to those skilled in the art.

[0106] This invention relates primarily to a system and method for passivating multiple solar cells configured within a manufactured solar module. To provide background to these aspects of the invention, an exemplary configuration of a manufactured solar module 10 will first be referenced. Figure 1 and Figure 2 And is described.

[0107] Figure 1 and Figure 2 The illustration depicts a manufactured solar module 10, or solar module assembly, comprising an array of solar cells 12 arranged in a grid pattern within a housing 14. The solar module 10 is a crystalline silicon solar cell module, and it will be understood that the crystalline silicon solar cell module defines a solar module 10, wherein each of the solar cells 12 has a crystalline silicon substrate that functions as a photoelectric conversion component.

[0108] The outer casing 14 includes a transparent glass sheet 24a located at the front side 26 of the solar module 10 and a reflective back sheet 24b disposed at the rear side 28 of the solar module 10. In this way, the reflective back sheet 24b and the transparent glass sheet 24a respectively define the front and back casings of the solar module 10. The solar cell 12 is sandwiched between the front and back casings, as... Figure 2 As shown in the image.

[0109] The housing 14 further includes a rectangular frame 102 that extends around the periphery of the solar module 10. The frame 102 protects the edges of the solar module 10 and provides a mechanism for mounting the solar module 10 to a structure (e.g., a building roof). The frame 102 includes four elongated frame members 104, each of which is mounted to (and extends along) a respective edge of the solar module 10.

[0110] Figure 1 The diagram shows a top (front) view of the solar module 10, while Figure 2 Depict the cross-section of the solar module 10 taken along the dashed line A-A', as shown below. Figure 1 As shown in the figure. The solar module 10 has its system Figure 1 The length of the horizontal dimension and its system Figure 1 The width of its vertical dimension.

[0111] Figure 2 A plurality of solar cells 12 are depicted arranged in a substantially horizontal reference plane RP of the solar module 10. The reference plane RP is substantially parallel to the front and back sheets 24a, 24b of the solar module 10 and extends substantially centrally therebetween. Although, in the embodiment described herein, the solar module 12 is shown (in...) Figure 1 For example, a configuration may have fifty-four solar cells 12, but it will be understood that this configuration is only one of many possible configurations and does not depart from the scope of the invention.

[0112] Figure 2 The dashed arrow at the top indicates the direction of solar radiation incident on the solar module 10. Each of the solar cells 12 has a front surface 16 (on which light is incident during normal use) and a rear surface 18 opposite to the front surface 16. The front surface 16 is configured to substantially face the sun during use.

[0113] Solar cell 12 is sandwiched between a pair of encapsulation layers 20a, 20b, extending across solar module 10 (as shown in the image). Figure 1 (As shown in the horizontal direction), from one side of the solar module 10 to the other. The solar cells 12 are arranged in a planar array, extending in both the longitudinal and lateral directions of the solar module 10, as shown. Figure 1 As shown, encapsulation layers 20a and 20b extend in both the longitudinal and transverse directions to overlap the array of multiple solar cells 12.

[0114] refer to Figure 2The solar module 10 includes an electrical assembly 30 that connects multiple solar cells 12 together. The electrical assembly 30 is also connected to a circuit and is located outside the outer casing 14 of the solar module 10. In this way, the electrical assembly 30 can be configured to provide an electrical connection between two solar modules 10.

[0115] Solar cells 12 are arranged in columns extending across the width of the solar module 10. The solar cells 12 in each column are connected in series to form a string via an electrical assembly 30. Each of these strings is connected in parallel via the electrical assembly 30 (not shown), as will be readily apparent to those skilled in the art.

[0116] The electrical assembly 30 includes a plurality of foil connectors 32 for connecting the solar cells 12 together. Each foil connector 32 includes a plurality of parallel conductive components (e.g., wires, or wire portions) forming an electrical connection between two adjacent solar cells 12. A first end of each of the plurality of conductive components is overlapped onto the front surface 16 of the first solar cell, while a second end of the conductive component is disposed on the back surface 18 of the second solar cell, such as... Figure 2 As shown in the image.

[0117] The conductive components of the foil connector 32 are disposed in a film (not shown), which is configured to be insulating and optically transparent. The film also adheres the individual ends of the conductive components to the solar cell 12, so that the foil connector 32 is properly aligned with the solar cell 12.

[0118] The electrical assembly 30 includes an external connector 34 that extends from inside the solar module 10 (e.g., from inside the housing 14) to outside the solar module (e.g., to outside the housing 14). The external connector 34 passes through an opening 36 or a terminal in the backplate 24b of the housing 14, such as... Figure 2 As shown in the diagram, the external connector 34 is configured to form a connection (at one end) to the foil connector 32 located at the side end of the solar cell string; and at the opposite end, the external connector 34 is connectable to an external circuit.

[0119] The electrical assembly 30 includes a junction box 38 disposed on the back surface of the back sheet 24b of the outer housing 14 of the solar module 10. The junction box 38 is configured to cover (and thereby seal) an opening 36 in the housing 14 through which the external connector 34 exits the solar module 10 to prevent moisture from entering the housing 14 through the opening 36.

[0120] Now refer to Figure 3 and 4This describes a system 100 according to one aspect of the present invention for passivating a plurality of solar cells 12 within a manufactured solar module 10. The manufactured solar module 10 is configured as described above in relation to... Figure 1 and 2 The system 100 includes an external circuit 42, which is connectable to the electrical assembly 30 (not shown) of the solar module 10. Figure 3 (in the middle). External circuitry 42 includes a voltage source in the form of a power supply unit 44. The power supply unit 44 is configured to apply voltage to the electrical assembly 30, thereby injecting forward current into a plurality of solar cells 12 (not shown) disposed within the manufactured solar module 10. Figure 3 (in Chinese) The forward current causes passivation of defects in solar cells, which leads to an increase in the open-circuit voltage (Voc) and fill factor (FF) of the solar cell, thereby improving the performance of the solar module during use.

[0121] The external circuit 42 includes a pair of conductive wires 46, which are connected at one end to the junction box 38 of the solar module 10 and at the opposite end to the power supply unit 44. The junction box 38 includes a set of connection points 48 that define the positive and negative terminals of the electrical assembly 30 (as indicated by "+" and "-" markings). The power supply 44 includes corresponding sets of positive and negative terminals 50, to which the conductive wires 46 of the external circuit 42 are connected.

[0122] Power supply unit 44 receives power from the AC grid (not shown). Power supply unit 44 includes a transformer assembly configured to regulate the power received from the AC grid and thereby control the power output to solar module 10 (e.g., voltage / current). Power supply unit 44 includes a controller (not shown) configured to receive commands from a user of system 100 and to control the transformer assembly to adjust the power output to solar module 12 based on the user commands.

[0123] As described above, system 100 is used to passivate defects in the solar cells 12 of the manufactured solar module 10. Reference will now be made to... Figure 3 and 4 This describes the passivation method as an example.

[0124] The first method step 202 involves providing a manufactured solar module 10 comprising a plurality of solar cells 12, as referenced above. Figure 1 and 2 The plurality of solar cells 12 are connected via the electrical assembly 30 of the solar module 10.

[0125] The passivation method 200 continues with a second method step 204, in which the electrical assembly 30 of the solar module 10 is connected to the external circuitry 42 of the passivation system 100. Specifically, this second method step 204 involves coupling the junction box 38 of the electrical assembly 30 to the conductive line 46 of the external circuitry 42 of the passivation system 100, such as... Figure 3 As shown in the diagram, an electrical connection is thus established between the power supply unit 14 of the passivation system 100 and the solar cells 12 disposed within the solar module 10.

[0126] Once the solar module 10 is electrically coupled to the passivation system 100, the method continues to a third method step 206, in which a voltage source (e.g., power supply unit 44) is configured to apply voltage to the electrical assembly 30, causing forward current injection into the plurality of solar cells 12. The power supply unit 44 is controlled by a control unit (not shown) to apply voltage 10 for a period of time until the passivation of the solar cells 12 is completed (e.g., passivation period). Furthermore, the magnitude of the voltage output by the passivation system 100 (e.g., passivation voltage) and the duration of the voltage applied to the solar module 10 (e.g., passivation period) each define controllable variables of the passivation method 200.

[0127] Alternatively, the passivation system 100 may be configured to apply forward current (e.g., passivation current) to the solar module 10 via any suitable mechanism, as will be understood by those skilled in the art.

[0128] To clarify the meaning of the term "forward current," as applied during the aforementioned passivation methods, reference will now be made to... Figure 5 To describe the forward current, Figure 5 An example current-voltage (IV) curve of the solar module 10 is shown, which operates in both dark and lit conditions (corresponding to solid and dashed lines, respectively).

[0129] When the solar module 10 operates in dark conditions (e.g., when no light is incident on the solar cell 12), the forward current in the solar cell corresponds to the charge carrier flow through the solar cell 12 in the direction permitted by the built-in photodiode of the solar cell (e.g., as defined by the pn junction).

[0130] A forward bias is applied across the solar cell to generate a forward current (by... Figure 5 (Represented by the solid line above the horizontal axis). Under this forward current condition, negative charge carriers (e.g., electrons) flow to the positive electrode of the solar module, while positive charge carriers (e.g., holes) flow to the negative electrode. In this way, the forward current defines the positive current flowing through each of the solar cells 12.

[0131] If a reverse bias is applied to the solar cell (when it is not illuminated), a reverse current is obtained (as from...). Figure 5 (As shown by the solid lines to the left of the vertical axis and below the horizontal axis). This reverse bias condition corresponds to the charge carrier flow through the solar cell in a direction not permitted by the built-in photodiode. Therefore, only a very small reverse current is obtained under this type of reverse current condition.

[0132] When the solar module 10 is operated under normal lighting conditions (e.g., when light is incident on the solar cell), a negative photocurrent is established in the solar cell 12 caused by the absorption of photons (as by...). Figure 5 (Represented by the dashed line below the horizontal axis in the middle). Forward bias is generated in the solar cell (as by...). Figure 5 (Indicated by the dashed line on the upper right of the vertical axis in the middle), as will be understood by those skilled in the art. A load can be applied to the solar cell to generate electricity.

[0133] The method of the present invention involves supplying a forward current to a solar cell 12. This forward current (e.g., a positive current) has the opposite polarity (e.g., a negative photocurrent) to the normal operating current of the solar cell. In this way, the method of the present invention can be defined as operating the solar cell using a “reverse” current (e.g., a forward current) that is “opposite” to the direction experienced during its normal operation (i.e., when illuminated).

[0134] Each of the controllable variables can be controlled (e.g., by passivation system 100) to optimize the passivation of a particular solar module 10. To demonstrate the advantages of passivation method 200, a series of experiments were conducted in which pre-manufactured solar modules 10 were passivated according to passivation method 200, and the controllable variables were adjusted for each module to produce different passivation conditions. The experimental results are graphically displayed. Figures 6 to 10 middle.

[0135] In Experiment A, nine single-sided solar modules (labeled A to I) were subjected to different values ​​of forward bias (voltage) and different time periods, as shown in Tables 1 and 2 below. The operational performance characteristics of the nine solar modules A to I were tested before undergoing passivation method 200. These “initial” performance tests determined the pre-passivation photovoltaic performance characteristics (e.g., current-voltage characteristics) of each module 10 under illumination conditions. After the preliminary performance tests, each solar module 10 underwent different passivation methods 200, which included different values ​​of controllable variables (identified by the “Applied Current” and “Duration” fields shown in Tables 1 and 2 below). After the passivation method 200 was completed, solar modules A to I then underwent “final” performance tests to determine their individual post-passivation photovoltaic performance characteristics.

[0136] For this experiment, at least some solar modules 10 received different voltages (forward bias) to induce different forward currents within the solar modules. For example, a current of 10A (e.g., +10A) was induced in solar module A, while a current of 33A (e.g., +33A) was induced in solar modules B through G, and solar modules H and I each received a current of 44A (e.g., +44A). Some solar modules experienced the same voltage level, but at different time periods. For example, solar modules B through G were each supplied with a current of 33A, but with a processing time increasing from approximately 15 minutes (B) to 120 minutes (G).

[0137] The effects of different passivation methods on the performance characteristics of solar modules A through I are shown in Tables 1 and 2 below. Specifically, Table 1 describes the changes in fill factor and open-circuit voltage, while Table 2 describes the changes in power at the point of maximum power (MPP). The results of Experiment A are also graphically displayed. Figures 6 to 8 middle.

[0138] Table 1 - Experiment A - Fill Factor and Open Circuit Voltage

[0139] Considering the results shown in Table 2, the greatest difference in power at the MPP was observed between solar modules D and G, which were passivated at a current of 33A for at least 30 minutes. Solar module F achieved the greatest absolute increase in power at the MPP. However, the greatest percentage increase in fill factor was observed with solar module G (summarized in Table 3 below), which was passivated at a current of 33A for 120 minutes.

[0140] Table 2 - Experiment A - Maximum Electric Point (MPP)

[0141] Solar modules A through I each have an imppp of approximately 10 amps, a short-circuit current of approximately 10.5 amps, and an overload current of 25 amps. The highest-performance solar modules D through G are passivated with short-circuit and overload currents exceeding those of the module. However, an increase in power at the MPP value was also observed in solar module A, which was passivated with a current of approximately 10 A, below the overload current and substantially equal to the imppp. Furthermore, note that increasing the current does not necessarily lead to a further increase in power at the MPP. For example, solar modules H and I (44 A, 30 minutes) achieved a similar increase in power at the MPP as solar module C, which was passivated for a similar period (30 minutes) but with a significantly lower current (33 A).

[0142] Further experiments involved a solar module passivated at a current of 70A for 10 minutes, resulting in an increase in power at the MPP of 1.4W. Module B achieved a similar increase in power at the MPP, having been passivated at a current of 33A for 15 minutes. Therefore, increasing the current (e.g., 70A) is not considered beneficial for the passivation of the solar module itself, but it reduces the amount of time required to perform the passivation method.

[0143] Table 3 - Experiment A - Optimal Passivation

[0144] Similar experiments were performed on three solar modules, where the passivation method involved injecting a current of 33A into each module for 30 seconds, 2 minutes, and 5 minutes respectively. Further experiments were conducted in which two solar modules were passivated with a current of 50A for 30 seconds and 2 minutes respectively. Simultaneously, an experiment was performed in which a solar module was passivated with a current of 70A for 5 minutes. In all of these experiments, no change in MPP was observed in the performance tests before and after passivation.

[0145] Table 4 shows the effect of injecting current into the solar module on the module's temperature (over time). The results are also graphically displayed. Figure 9 The results corresponding to modules C, D, E, and G indicate that the temperature of their solar module 10 increases over time for a constant injection current (33A). Furthermore, a comparison of the performance results of solar modules D and I indicates that the temperature of their solar cells increases with increasing injection current (e.g., from 33A to 44A, respectively) for a similar passivation period.

[0146] Table 4 - Experiment A - Temperature

[0147] The relationship between the applied voltage and temperature of the solar module will be referenced in Table 5 below. Figure 10 This will be discussed further. In this second experiment B, the solar module was passivated with a current of 33A for 60 minutes. The current was maintained at a constant value (33A), and the voltage required to maintain this current was measured every 5 minutes. At the same time, the temperature was measured at the same 5-minute intervals.

[0148] Table 5 - Experiment B - Voltage vs. Temperature

[0149] The passivation voltage required to achieve a constant current (33A) decreases over time as temperature increases. Specifically, the voltage decreases slowly and then stabilizes as time and temperature increase. This is due to the decrease in the resistance of the solar module, as temperature increases due to the flow of current.

[0150] It will be understood that the voltage required to achieve a given current (e.g., 33A) depends on the resistance value associated with the plurality of solar cells 12 connected together within the solar module 10 (e.g., the type and number of solar cells). For example, a large number of solar cells (e.g., 66 or 72 solar cells) will exhibit better performance than those installed in a single unit. Figure 1 The fifty-four solar cells 12 within module 10 shown have a larger resistance value. A larger resistance value will require a larger voltage (e.g., passivation voltage) to achieve the same current value.

[0151] According to the exemplary configuration, the solar module 10 is manufactured by stacking a plurality of solar cells 12 within an outer housing 14 of the module 10. Such manufacturing methods typically involve sandwiching a plurality of solar cells 12 (and encapsulation layers 20a, 20b) between front and back sheets 24a, 24b before applying heat and pressure to bond the solar module 10 together. According to the exemplary passivation method 200 of the present invention, voltage is applied only to the solar module 10 once the heat from the manufacturing process has been at least partially dissipated from the plurality of solar cells 12.

[0152] For example, passivation method 200 may only involve continuing method step 206 based on the condition that the temperature of the plurality of solar cells 12 is below a predetermined temperature (e.g., room temperature, approximately 25°C). In this exemplary method, method step 206 includes monitoring the temperature of the solar cells 12 within the solar module 10. For example, the temperature of the solar cells 12 can be measured directly using an infrared thermometer. Then, the passivation method continues only when the measured temperature of the solar cells 12 drops below the predetermined temperature.

[0153] Note: Solar modules A through I from Experiment A were allowed to cool to near room temperature before passivation method 200 was applied. In a further exemplary experiment C, solar module 10 was passivated according to method 200, but in this case, the method involved immediately followed the lamination process by connecting solar cell 12 to passivation system 100, and voltage was subsequently applied while the solar cell was still at an elevated temperature. Specifically, the solar module was passivated at a current of 33A for a period of 30 minutes, which is equivalent to solar modules C and D from Experiment A. However, unlike solar modules C and D from Experiment A, the solar module from Experiment C resulted in no substantial increase in the MPP of the solar module.

[0154] In another embodiment of Experiment C, the solar module was further passivated with a current of 33A for a period of 15 minutes, equivalent to solar module B from Experiment A. In this case, the "thermally stacked" and passivated solar modules exhibited an increase in MPP of 0.9 W. However, this corresponding increase in MPP is still less than 1.2 W, achieved by the equivalent "cold" solar module B from Experiment A. The applicant has discovered that the method according to the present invention can achieve increased passivation of multiple solar cells within a solar module (when the solar cells are not heated by an external source), or prevent them from remaining at elevated temperatures after the process of manufacturing the solar module.

[0155] In the graphics, the thickness of sheets, layers, films, etc., is exaggerated for clarity. Furthermore, it will be understood that when a component such as a layer, film, region, or substrate is described as being "on" another component, it can be directly on the other component or there may be an intermediate component. Conversely, when a component is described as being "directly" on another component, there is no intermediate component.

Claims

1. A method for passivating a plurality of solar cells disposed within at least partially manufactured solar modules, wherein the solar module includes a plurality of solar cells and an electrical assembly connecting the plurality of solar cells together into one or more solar cell strings, wherein the electrical assembly is connectable to a circuit located outside the solar module, wherein the method comprises: The electrical assembly is connected to an external circuit, which includes a current supply; and The current supply is used to supply a forward current to the plurality of solar cells; and The step of supplying the forward current is performed either before or after the stacking of the solar module.

2. The method of claim 1, wherein the at least partially manufactured solar module comprises the plurality of solar cells disposed within a housing of one of the solar modules.

3. The method of claim 2, wherein the housing of the at least partially manufactured solar module comprises a front sheet and a back sheet, wherein the at least partially manufactured solar module comprises an encapsulation inserted therebetween with the plurality of solar cells between the front sheet and the back sheet and heated to bond the solar cells to the housing to form the at least partially manufactured solar module; wherein: The step of supplying the forward current is performed after the stacking of the solar module; and The method further includes allowing the heat from the at least partially manufactured solar module to dissipate at least partially from the plurality of solar cells before supplying forward current to the plurality of solar cells.

4. The method of any of the preceding claims, wherein the method comprises supplying forward current to the plurality of solar cells depending on whether the temperature of the plurality of solar cells is at or below a predetermined temperature.

5. The method of claim 4, wherein the predetermined temperature is room temperature, selectively 20°C.

6. The method of any of the preceding claims, wherein the magnitude of the forward current supplied to the plurality of solar cells is greater than or equal to the magnitude of a rated current of at least one of the solar cells.

7. The method of claim 6, wherein the forward current supplied to the plurality of solar cells is at least 12A.

8. The method of claim 6 or 7, wherein the magnitude of the forward current supplied to the plurality of solar cells is greater than or equal to the magnitude of a short-circuit current of at least one of the solar cells.

9. The method of any one of claims 6 to 8, wherein the magnitude of the forward current supplied to the plurality of solar cells is greater than the magnitude of the rated current of one of the solar cells.

10. The method of claim 9, wherein the magnitude of the forward current supplied to the plurality of solar cells is greater than or equal to the magnitude of the short-circuit current of one of the solar modules.

11. The method of claim 10, wherein the method comprises supplying a forward current to the plurality of solar cells, the forward current being at least 314% of the short-circuit current of the solar module.

12. The method of any of the preceding claims, wherein the method comprises supplying forward current to the plurality of solar cells for at least 30 seconds, selectively at least 1 minute, and further selectively at least 120 minutes.

13. The method as claimed in any of the preceding claims, wherein: The current supply includes a voltage source; and The step of supplying the forward current includes configuring the voltage source to apply a forward voltage to the electrical assembly, thereby using the voltage source to supply the forward current to the plurality of solar cells.

14. The method of any of the preceding claims, wherein the forward current is applied to the plurality of solar cells when the solar module is in dark conditions.

15. The method of any of the preceding claims, wherein each of the plurality of solar cells comprises a crystalline silicon substrate.

16. The method of any of the preceding claims, wherein one or more of the plurality of solar cells is a heterojunction technology (HJT) solar cell.

17. A method for at least partially manufacturing a solar module, wherein the method comprises: A power assembly is used to connect multiple solar cells into one or more solar cell strings, and this power assembly can be connected to a circuit located outside the solar module; and The plurality of solar cells are passivated within the solar module manufactured in at least a portion of any one of claims 1 to 16.

18. The method of claim 17, wherein: The method further includes stacking the solar module; and The step of supplying the forward current as part of passivating the plurality of solar cells is performed before or after the step of stacking the solar module.

19. The method of claim 17 or 18, wherein the method further comprises configuring the plurality of solar cells within the housing of one of the solar modules.

20. The method of claim 19, wherein the housing comprises a front sheet and a back sheet, wherein the method of at least partially manufacturing the solar module further comprises: The solar module and one of the plurality of solar cells are encapsulated between the front sheet and the back sheet of the housing; and The encapsulation is heated to engage the solar cell within the housing; in: The step of supplying the forward current as part of passivating the plurality of solar cells is performed after stacking the solar module; and The passivation step of the plurality of solar cells further includes allowing the heat from the heating of the encapsulation to dissipate at least partially from the plurality of solar cells before supplying forward current to the plurality of solar cells.

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