Patent Description:
A photovoltaic module is a device that directly converts light energy into electrical energy through a photoelectric effect or a photochemical effect. The photovoltaic module may be a silicon-based photovoltaic module, a gallium arsenide (GaAs) photovoltaic module or a perovskite photovoltaic module and the like. As a most promising photovoltaic cell in the third generation of solar cells, a perovskite photovoltaic module has been greatly improved in terms of energy conversion efficiency in the past ten years. Due to a low manufacturing cost of the perovskite photovoltaic module, the perovskite photovoltaic module is expected to play a huge role in the energy field.

A packaging technology can separate a cell string in a photovoltaic module from an external environment, preventing pollution and corrosion of various impurities, and is a method to improve a service life of a precision electronic element. However, because materials in a perovskite photovoltaic module are sensitive to water vapor, oxygen, pressure, etc. in the air, an existing packaging technology cannot meet what is needed, and the service life of the photovoltaic module still needs to be increased. <CIT> discloses a photovoltaic module comprising an impurity detection layer in contact with the electrodes.

The subject matter of the present invention is defined in claim <NUM>.

Embodiments of the present disclosure provide a photovoltaic module, to improve packaging technology of the photovoltaic module, thereby prolonging service life of the photovoltaic module.

An embodiment of the present disclosure provides a photovoltaic module including: a base plate, a cell string and a cover plate stacked in order; a first packaging layer located between the base plate and the cover plate and surrounding the cell string, the first packaging layer, the base plate and the cover plate defining a first sealed space; and a moisture treatment layer located in the first sealed space. The moisture treatment layer includes at least one of a functional layer and a moisture detection layer. The functional layer is adaptive to absorb moisture and be converted into a solidified layer, and the solidified layer has a degree of crosslinking greater than a degree of crosslinking of the functional layer. The moisture detection layer is adaptive to detect and determine whether there is moisture in the first sealed space through response information of the moisture detection layer.

Further, the moisture treatment layer is at least located between the first packaging layer and the cell string.

Further, the cell string has a first surface and a second surface opposite each other, and a side surface connecting the first surface and the second surface, the first surface being away from the base plate, and the second surface facing the base plate; and the first surface includes a central region and a peripheral region surrounding the central region, and the moisture treatment layer is located on the side surface and on the first surface of the peripheral region.

Further, the moisture treatment layer is attached to the side surface and the first surface of the peripheral region.

Further, the photovoltaic module further includes a separation layer located on the side surface and the first surface of the peripheral region, the separation layer located between the moisture treatment layer and the cell string.

Further, the moisture treatment layer is further located on the first surface of the central region.

Further, the moisture treatment layer is arranged around the cell string, and the moisture treatment layer, the base plate and the cover plate define a second sealed space.

Further, there are corner junction regions between the first packaging layer and the base plate and between the first packaging layer and the cover plate, and the moisture treatment layer is located at least in the corner junction regions.

Further, the moisture treatment layer is further located on an inner wall surface of the first packaging layer facing the cell string.

Further, the photovoltaic module further includes a second packaging layer filling the first sealed space.

Further, the base plate is a conductive substrate, and the cell string is a string of perovskite solar cell.

Further, the base plate is a bearing board, and the cell string is a string of perovskite solar cell.

Further, materials for the functional layer include a hydrolyzable and crosslinkable material.

Further, the functional layer includes a first functional layer and a second functional layer stacked in order, the first functional layer is located between the second functional layer and the cell string, a material for the first functional layer is a material that is already hydrolyzed and crosslinked based on a hydrolyzable and crosslinkable material, and materials for the second functional layer include a hydrolyzable and crosslinkable material.

Further, the hydrolyzable and crosslinkable material may be either silane modified polyurethane or silicone.

Further, materials for the first packaging layer include moisture-solidified materials, optical-solidified materials or additive-solidified materials.

Further, the moisture detection layer includes a moisture absorption color changeable layer, a moisture-sensitive resistor or a moisture-sensitive sensor.

An embodiment of the present disclosure further provides a photovoltaic module including: a base plate, a cell string and a cover plate stacked in order; a first packaging layer located between the base plate and the cover plate and surrounding the cell string, the first packaging layer, the base plate and the cover plate defining a third sealed space; and a solidified layer located within the third sealed space, materials for the solidified layer including a material converted from a hydrolyzable and crosslinkable material after absorbing moisture.

Further, the solidified layer is at least located between the first packaging layer and the cell string.

Compared with existing technologies, the technical solutions provided in the present disclosure at least have the following advantages.

The photovoltaic module provided in embodiments of the present disclosure includes a functional layer in a sealed space. The functional layer is adaptive to absorb moisture and be converted into a solidified layer with a degree of cross linking greater than a degree of cross linking of the functional layer. Therefore, the functional layer may absorb moisture and be converted into a solidified layer after absorbing the moisture, thereby automatically performing packaging on the photovoltaic module for a second time. In this way, the moisture is prevented from damaging a cell string, thereby tightness of the package is improved, the packaging technology for the photovoltaic module is improved, and the service life of the photovoltaic module is prolonged.

In addition, the photovoltaic module includes a moisture detection layer located in a sealed space. It is detected and determined whether there is moisture in the sealed space through response information of the moisture detection layer. Therefore, when moisture enters the sealed space, an operator may perform re-packaging on the photovoltaic module in time according to a detection result on the moisture detection layer, thereby moisture is further prevented from damaging the cell string, and the service life of the photovoltaic module is further prolonged.

One or more embodiments are described as examples with reference to the corresponding figures in the accompanying drawings, and the examples do not constitute a limitation to the embodiments. The figures in the accompanying drawings do not constitute a proportion limitation unless otherwise stated.

It is known from the above background that a packaging technology and a service life of a photovoltaic module need to be improved.

It is found through analysis that reasons for the above is that during packaging of a photovoltaic module, it is common that a package is not packaged tight enough; during use of the photovoltaic module, it is common for a packaging material to age due to light, heat and water. Therefore, under moisture, it is easy for a cell string to be decomposed or less efficient and cease to work.

In order to address the problems, an embodiment of the present disclosure provides a photovoltaic module and a manufacturing method for the photovoltaic module. The photovoltaic module has a functional layer for absorbing moisture and being converted into a solidified layer, the solidified layer having a degree of cross linking greater than that of the functional layer. Therefore, in a case where packaging is not tight enough or the packaging material ages, the functional layer may absorb moisture and becomes a solidified layer to be packaged a second time, thereby moisture may be blocked out and the packaging is enhanced.

An embodiment of the present disclosure provides a photovoltaic module and a manufacturing method for the photovoltaic module. The photovoltaic module has a moisture detection layer. It is detected and determined whether there is moisture in a sealed space through response information of the moisture detection layer. Therefore, in a case where packaging is not tight or a packaging material ages, the moisture detection layer may quickly detect moisture in the sealed space. Based on response information of the moisture detection layer, an operator may re-package the photovoltaic module, thereby service life of the photovoltaic module is prolonged.

An embodiment of the present disclosure further provides a photovoltaic module having a functional layer and a moisture detection layer. The functional layer is adaptive to absorb moisture and be converted into a solidified layer having a degree of cross linking greater than a degree of cross linking of the functional layer. The moisture treatment layer is adaptive to detect and determine whether there is moisture in a sealed space through response information of the moisture detection layer. Therefore, in a case where packaging is not tight or a packaging material ages, the functional layer may absorb moisture in the sealed space and be converted into a solidified layer to block moisture from entering the cell string, thereby a second packaging is realized. In addition, the moisture detection layer may detect and locate a particular position of the moisture so that an operator may re-package the photovoltaic module, thereby service life of the photovoltaic module is prolonged.

In order to make the objective, the technical solution and advantages of the present disclosure clearer, a detailed description is provided on embodiments of the present disclosure with reference to the drawings. However, those skilled in the art may appreciate that in the embodiments of the present disclosure, a plurality of technical details are provided for readers to better understand the present disclosure. However, even if the technical details and variants and amendments based on the following embodiments are not provided, the technical solution that the present disclosure claims to protect can still be implemented. <FIG> are schematic diagrams showing structures of a photovoltaic module provided in a first embodiment of the present disclosure.

With reference to <FIG>, the first embodiment of the present disclosure provides a photovoltaic module including: a base plate <NUM>, a cell string <NUM> and a cover plate <NUM> staked in order; a first packaging layer <NUM> located between the base plate <NUM> and the cover plate <NUM> and surrounding the cell string <NUM>, the first packaging layer <NUM>, the base plate <NUM> and the cover plate <NUM> defining a first sealed space; a functional layer <NUM> located within the first sealed space, adaptive to absorb moisture and be converted into a solidified layer, and the solidified layer having a degree of cross linking greater than that of the functional layer.

A further description is provided in details in the following with reference to the drawings.

With reference to <FIG>, the base plate <NUM> may be a conductive substrate, and the cell string <NUM> may be a string of perovskite solar cell. That is, in this embodiment, the base plate <NUM> can not only bear the cell string <NUM>, but also can serve as an anode to collect electrons generated by the cell string <NUM> after light exposure. The base plate <NUM> may be fluorine-doped tin oxide conductive glass or indium tin oxide conductive glass. It may be appreciated that the conductive base plate may be conductive glass of the perovskite solar cell.

In this embodiment, the cell string <NUM> is a perovskite solar cell film layer including such structures as a hole transport layer, a perovskite layer, an electron transport layer and a metal electrode. When exposed to sunlight, the perovskite layer first absorbs photons to generate electron-hole pairs. Un-recombined electrons and holes are separately collected by the electron transport layer and the hole transport layer. That is, the electrons are transmitted from the perovskite layer to the electron transport layer and finally collected by the base plate <NUM>; the holes are transmitted from the perovskite layer to the hole transport layer and finally collected by the metal electrode. At last, photocurrent is generated through a circuit connecting the base plate <NUM> and the metal electrode. Because a perovskite material has a low carrier recombination probability and a high carrier transferring rate, a diffusion distance and a life of a carrier are relatively long. Therefore, the perovskite solar cell has a high photoelectric conversion efficiency.

In another embodiment, the cell string may further include such cell film layers as gallium arsenide, copper indium selenium or cadmium telluride layers.

It may be appreciated that the cell string <NUM> is of a cell structure formed by a plurality of solar cells connected in parallel or in series. For example, the cell string may include a plurality of sub-strings connected in parallel or in series, and each of the plurality of sub-strings may further include a plurality of solar cells connected in series.

In this embodiment, the cover plate <NUM> may be glass. In another embodiment, the cover plate may be transparent plastic.

The first packaging layer <NUM> may be located between the base plate <NUM> and the cover plate <NUM>, surrounding the cell string <NUM>. The first packaging layer <NUM>, the base plate <NUM> and the cover plate <NUM> define the first sealed space.

A material for the first packaging layer <NUM> may be a moisture-solidified material, a light-solidified material or an additive-curing material, for example, polyisobutylene, polyolefin or polyurethane. Because the perovskite solar cell is not resistant to a high temperature, temperature should not be too high during a lamination process of the photovoltaic module. If the first packaging layer <NUM> is a thermos-solidified material, it is difficult for the temperature during the lamination process to reach a temperature at which the first packaging layer <NUM> is solidified, thus the first packaging layer <NUM> may not be solidified completely, resulting in inadequate packaging. Therefore, the moisture-solidified material, the light-solidified material or the additive-curing material are used for the first packaging layer <NUM> to avoid the above problem. In this way, the first packaging layer <NUM> may be solidified well without a high temperature.

A width of the first packaging layer <NUM> in a direction parallel to a surface of the base plate <NUM> is <NUM>-<NUM>. It shall be noted that if a width of the first packaging layer <NUM> is too small, it would be easy for a problem of inadequate packaging to occur; but if the width is too large, an area of the photovoltaic module would be increased. Therefore, the above two problems may be avoided if the width of the first packaging layer <NUM> is <NUM>-<NUM>.

With reference to <FIG>, in this embodiment, the first sealed space may be further filled with a second packaging layer <NUM>.

The second packaging layer <NUM> may further enhance sealing to avoid moisture intrusion.

A material for the second packaging layer <NUM> differs from that of the first packaging layer <NUM>, and may be an ethylene vinyl acetate (EVA) film layer.

In another embodiment, the material for the second packaging layer <NUM> may be identical with that of the first packaging layer <NUM>. Alternatively, there may not be a second packaging layer in the first sealed space, i.e., there is a gap in the first sealed space.

The functional layer <NUM> is located within the first sealed space. If either the first packaging layer <NUM> or the second packaging layer <NUM> is not packaged adequately or has aged material, the functional layer <NUM> may absorb moisture and be converted into a solidified layer. The solidified layer has a degree of cross linking greater than that of the functional layer <NUM>. That is, the functional layer <NUM> may perform packaging on the cell string <NUM> for a second time, thereby preventing the cell string <NUM> from being decomposed or ceasing to be effective in moisture.

It may be appreciated that in this embodiment, what the functional layer <NUM> absorbs may be moisture entered the first sealed space, and the functional layer <NUM> prevents the moisture in the first sealed space from damaging the cell string <NUM>.

The degree of cross linking is further called cross linking index or cross linking density, and may be used to represent a degree of cross linking of a molecular chain. In particular, the degree of cross linking refers to a fraction taken by a cross-linked structural unit of an entire structural unit. The degree of cross linking is proportional with the amount of cross link bonds: the greater the degree of cross linking, the more cross link bonds in a unit volume and the greater the cross linking density. A thickness of the functional layer <NUM> is greater than or equal to <NUM>. If the thickness of the functional layer <NUM> is excessively thin, a compactness of the functional layer <NUM> is poor after absorbing moisture. Therefore, the thickness of the functional layer <NUM> is at least <NUM>, thereby improving the second packaging effect.

In this embodiment, a material for the functional layer <NUM> may be a hydrolyzable and crosslinkable material that can absorb moisture entering into the first sealed space and that may have a cross-linking reaction after absorbing moisture. In this way, viscosity and compactness of the material are increased, and the second packaging may be performed.

The hydrolyzable and crosslinkable material may be silane modified polyurethane or silicone. In addition, the hydrolyzable and crosslinkable material may be either a single-component hydrolyzable and crosslinkable material or a double-component hydrolyzable and crosslinkable material.

In another embodiment, apart from the hydrolyzable and crosslinkable material, materials for the functional layer may further include a material that is already hydrolyzed and cross-linked.

For silane-modified polyurethane, a prepolymer thereof has an aminosilane end cap, and the prepolymer reacting with external moisture may produce a cross-linked network structure. In addition, an organic functional silane has multiple functions. Firstly, the silane acts as an adhesion promoter to improve bonding; secondly, in a crosslinking process, the silane can accelerate a reaction.

For silicone, a main polymer chain thereof is composed of silicon-oxygen-silicon bonds, and does not contain a structure that may be polymerized by heating. That is, even at a high temperature, silicone is not prone to polymerize. Therefore, in subsequent use or packaging, silicone is not easily affected by temperature and can maintain good moisture absorption and crosslinking properties.

It may be appreciated that different hydrolyzable and crosslinkable materials for the functional layer <NUM> may enable the functional layer <NUM> to have different reactions internally when the functional layer is converting to a solidified layer. For example, the functional layer <NUM> may have a hydrolysis reaction, a polycondensation reaction, a cross-linking reaction, or an oligomerization reaction and the like. For example, when the material for the functional layer <NUM> is silane-modified polyurethane, the functional layer <NUM> undergoes a cross-linking reaction, and the number of Si-O-Si bonds in the solidified layer is greater than the number of Si-O-Si bonds in the functional layer <NUM>. In another example, the compactness of the solidified layer may further be greater than the compactness of the functional layer.

In addition, it shall further be noted that the functional layer <NUM> absorbs moisture in the first sealed space and is converted into a solidified layer, including: a partial region of the functional layer <NUM> absorbs moisture to be converted into a solidified layer. Alternatively, all of the functional layer <NUM> absorbs moisture to be converted into a solidified layer. In this embodiment, the functional layer <NUM> includes a first functional layer and a second functional layer stacked in order, the first functional layer is located between the second functional layer and the cell string <NUM>, the material for the first functional layer is a material that is already hydrolyzed and crosslinked based on a hydrolyzable and crosslinkable material, and materials for the second functional layer includes the hydrolyzable and crosslinkable material.

Since a non-hydrolysed and non-cross-linked material has flowability, while a hydrolysed and cross-linked material is highly adhesive, thus stacking the non-hydrolysed and non-cross-linked material and the hydrolysed and cross-linked material may reduce the flowability of the non-hydrolysed and non-cross-linked material, thereby thickness of the functional layer is more even.

In another embodiment, the functional layer may be a single-layered hydrolyzable and crosslinkable material, i.e., a material that is not hydrolyzed yet.

The functional layer <NUM> is at least located between the first packaging layer <NUM> and the cell string <NUM>. In case of inadequate packaging or aged packaging of the first packaging layer <NUM> or the second packaging layer <NUM>, a space between the first packaging layer <NUM> and the cell string <NUM> is a place where moisture enters earliest. Therefore, the functional layer <NUM> is provided between the first packaging layer <NUM> and the cell string <NUM>, thereby enhancing the second packaging effect.

For technical solutions about a particular position of the functional layer <NUM> in the first sealed space, the following examples are mainly included:.

The separation layer <NUM> can further improve tightness of the package, and the separation layer <NUM> can also separate the functional layer <NUM> from the cell string <NUM>. If the material used for the functional layer <NUM> may react with the material for the cell string <NUM>, the separation layer <NUM> can prevent the functional layer <NUM> from having an adverse effect on the cell string <NUM> and improve life of the cell string <NUM>. A material for the separation layer <NUM> may be an EVA film.

Example Three: with reference to <FIG>, the functional layer <NUM> is further located on the first surface <NUM> of the central region <NUM>. That is, the functional layer <NUM> is located on the side surface <NUM> and the first surface <NUM> of the cell string <NUM>. A separation layer <NUM> is further included between the functional layer <NUM> and the cell string <NUM>. It may be appreciated that the functional layer <NUM> can further be directly attached to the side surface <NUM> and the first surface <NUM> of the cell string <NUM>, that is, there is no separation layer <NUM> between the functional layer <NUM> and the cell string <NUM>.

Example Four: with reference to <FIG>, the functional layer <NUM> is arranged around the cell string <NUM>, and the functional layer <NUM>, the base plate <NUM> and the cover <NUM> define a second sealed space. That is, the functional layer <NUM> is arranged around the side surface <NUM> of the cell string <NUM> and encloses the cell string <NUM> in the second sealed space.

The functional layer <NUM> may be arranged close to a side surface of the cell string <NUM>, or there may be a gap between the functional layer <NUM> and the side surface of the cell string <NUM>; or there may be a separation layer between the functional layer <NUM> and the side surface <NUM> of the cell string <NUM>.

Example Five: with reference to <FIG>, there are corner junction regions between the first packaging layer <NUM> and the base plate <NUM>, and between the first packaging layer <NUM> and the cover plate <NUM>, and the functional layer <NUM> is located at least in the corner junction regions. That is, the functional layer <NUM> covers a boundary between the first packaging layer <NUM> and the cover plate <NUM> and the base plate <NUM>.

Example Six: with reference to <FIG>, the functional layer <NUM> is further located on an inner wall surface of the first packaging layer <NUM> facing the cell string <NUM>.

Example Seven: with reference to <FIG>, the functional layer <NUM> fills the first sealed space. At this time, the functional layer <NUM> completely covers the cell string <NUM>, and the functional layer <NUM> has a great thickness and can perform sealing well.

As shown in <FIG>, the functional layer <NUM> is converted into a solidified layer after absorbing moisture, and the solidified layer is glued to the base plate <NUM>, the first packaging layer <NUM> and the cover plate <NUM>, thereby further improving sealing performance of the packaging structure.

To sum up, there is the functional layer <NUM> in the first sealed space of the photovoltaic module in this embodiment. The functional layer <NUM> can absorb moisture in the first sealed space, and can further be converted into a solidified layer after absorbing moisture to block intrusion of moisture, thereby prolonging service life of the cell string <NUM>.

A second embodiment of the present disclosure provides a photovoltaic module substantially identical with the photovoltaic module provided in the first embodiment, but differs in that in this embodiment, a base plate may be a bearing board and a cell string is a string of perovskite solar cell. In this embodiment, the first embodiment may be referred to for portions identical or similar to the photovoltaic module provided in the first embodiment, and content of the portions is not repeated. <FIG> are schematic diagrams showing structures of a photovoltaic module provided in this embodiment.

Detailed description is provided in the following with reference to the drawings.

With reference to <FIG>, in this embodiment, the photovoltaic module includes: a base plate <NUM>, a cell string <NUM> and a cover plate <NUM> stacked in order; a first packaging layer <NUM> located between the base plate <NUM> and the cover plate <NUM> and surrounding the cell string <NUM>, the first packaging layer <NUM>, the base plate <NUM> and the cover plate <NUM> defining a first sealed space; a functional layer <NUM> located within the first sealed space. The functional layer <NUM> is adaptive to absorb moisture and be converted into a solidified layer, and the solidified layer having a degree of cross linking greater than that of the functional layer <NUM>.

In this embodiment, the base plate <NUM> may be a bearing board and the cell string <NUM> is a string of perovskite solar cell. That is, the base plate <NUM> is adaptive to bear the cell string but does not have a function of collecting electrons. The base plate <NUM> may be glass or transparent plastic.

The cell string <NUM> includes a conductive glass <NUM> and a perovskite solar cell film layer <NUM>. As an anode of a perovskite solar cell, the conductive glass <NUM> is used for collecting electrons.

With reference to <FIG>, there is a second packaging layer <NUM> between the cell string <NUM> and the base plate <NUM>. The second packaging layer <NUM> may improve tightness of packaging.

It may be appreciated that the cell string <NUM> may be directly placed on the base plate <NUM>; or there may be a functional layer and/or a second packaging layer between the cell string <NUM> and the base plate <NUM>.

To sum up, the base plate <NUM> of the photovoltaic module provided in this embodiment is a bearing board. A second packaging layer <NUM> or a functional layer <NUM> may be provided between the bearing board and the cell string <NUM> to improve the tightness of the package. In addition, the functional layer <NUM> in the first sealed space can absorb moisture in the first sealed space, and can further be converted into a solidified layer after moisture absorption, preventing intrusion of moisture, thereby prolonging service life of the cell string <NUM>.

A third embodiment of the present disclosure provides a photovoltaic module substantially identical with the photovoltaic module provided in the first embodiment and the second embodiment. The photovoltaic module includes: a base plate, a cover plate, a cell string, a first packaging layer, a second packaging layer and a functional layer. A main difference between this embodiment and previous embodiments lies in that the photovoltaic module provided in this embodiment includes a moisture detection layer. For identical or similar portions of the photovoltaic module between this embodiment and the first and second embodiments, the first and second embodiments may be referred to and the content is not repeated here. <FIG> are schematic diagrams showing structures of a photovoltaic module provided this embodiment.

With reference to <FIG>, a base plate <NUM> of a conductive base plate is taken as an example. It may be appreciated that the base plate <NUM> may alternatively be a bearing board. There is no limitation to a base plate in this embodiment.

A moisture detection layer <NUM> is located within a sealed space. It is detected and determined whether there is moisture in the sealed space through response information of the moisture detection layer <NUM>. Therefore, when moisture enters the sealed space, the moisture detection layer <NUM> can detect the moisture quickly so that an operator may perform re-packaging on the photovoltaic module according to the response information.

The response information may be color information or photoelectrical information. The color information is taken as an example. The response information includes a first response information and a second response information. The first response information is that color remains unchanged, i.e., no moisture enters the sealed space. The second response information is that the color changes, i.e., moisture enters the sealed space. Therefore, if the response information of the moisture detection layer <NUM> is the second response information, the operator performs re-packaging on the photovoltaic module.

The moisture detection layer <NUM> includes a moisture absorption color changeable layer, a moisture-sensitive resistor or a moisture-sensitive sensor.

The moisture absorption color changeable layer changes its color after absorbing moisture. According to the change state of color, it may be determined whether there is moisture in the sealed space. In addition, a particular position of the moisture may be determined according to a particular position of color change of the moisture absorption color changeable layer. Therefore, the operator may locate the position of the moisture and perform re-packaging on the photovoltaic module in regard to the position where the moisture enters.

Materials for the moisture absorption color changeable layer may be: copper sulfate, cobalt chloride, methylene amines or organic phenols.

Resistance of the moisture-sensitive resistor may change after absorbing moisture, and based on the change, it may be determined whether there is moisture in the sealed space. In addition, a plurality of moisture-sensitive resistors may be arranged in the sealed space as separated from each other. A particular position of the moisture may be determined in regard to resistance changes of the moisture-sensitive resistors in different positions.

The moisture-sensitive sensor may detect humidity change and convert the humidity to a signal to be sent out. Based on the signal, it may be determined whether there is moisture in the sealed space. In addition, a plurality of moisture-sensitive sensors may be arranged in the sealed space as separated from each other. A particular position of the moisture may be determined in regard to signals of the moisture-sensitive sensors in different positions.

For positions of the moisture detection layer <NUM> in the sealed space, the following examples are mainly included:.

It shall be noted that the moisture detection layer <NUM> may further be located at another position in the sealed space. A position of the moisture detection layer <NUM> is not limited in this embodiment.

To sum up, the photovoltaic module provided in this embodiment has a moisture detection layer capable of detecting and locating moisture in a sealed space. Therefore, an operator may perform re-packaging on the photovoltaic module according to response information of the moisture detection layer, so as to prevent a cell string from being damaged by moisture.

A fourth embodiment of the present disclosure provides a manufacturing method for a photovoltaic module. <FIG> is a flowchart showing a manufacturing method of a photovoltaic module provided in this embodiment of the present disclosure.

With reference to <FIG> and <FIG>, at step S400, a base plate <NUM>, a cell string <NUM> and a cover plate <NUM> are provided. The cell string <NUM> is stacked on the base plate <NUM>.

In this embodiment, the base plate <NUM> may be a conductive substrate, the cell string <NUM> is a perovskite solar cell film layer. The cell string <NUM> is attached to the surface of the base plate <NUM>, the cell string <NUM> includes a plurality of perovskite solar cells, and the conductive substrate may be conductive glass of the plurality of perovskite solar cells.

In another embodiment, a base plate may be a bearing board, a cell string may be a string of perovskite solar cell, and the cell string includes a conductive substrate and a perovskite solar cell film layer. The cell string may be attached to the base plate, or a functional layer and/or second packaging layer may be arranged between the cell string and the base plate.

It shall be noted that manufacturing of a photovoltaic module shall be performed in inert gas to prevent moisture in the outside from damaging the cell string <NUM>.

At step S401, a first packaging layer <NUM> is formed on the base plate <NUM> and around the cell string <NUM>, and a functional layer <NUM> is formed on the base plate <NUM>.

Before forming the functional layer <NUM>, the manufacturing method further includes: preprocessing the material for the functional layer <NUM> to improve adhesion of the material for the functional layer <NUM>. A reason mainly lies in that the material for the functional layer <NUM> has a certain flowability before absorbing moisture, and the preprocessing on the material for the functional layer <NUM> may reduce the flowability of the functional layer <NUM>, thereby improving evenness of thickness of the functional layer <NUM> and ensuring a result of a second packaging.

In particular, the material for the functional layer <NUM> may be mixed with additives such as catalyst, filler and plasticizer into paste or half-solidified liquid in inert gas or vacuum.

A height of the first packaging layer <NUM> is higher than a height of the cell string <NUM> in order to guarantee that the cell string <NUM> is in a space completely sealed after the cover plate <NUM> is placed.

It may be appreciated that an order of forming the first packaging layer <NUM> and the functional layer <NUM> is not fixed, but need to be adjusted according to a particular position arranged for the functional layer <NUM>.

For a technical solution for forming the first packaging layer <NUM> and the functional layer <NUM>, there may mainly be the following examples:
Example One: with reference to <FIG> and <FIG>, the functional layer <NUM> is formed earlier than the first packaging layer <NUM>.

The cell string <NUM> has a first surface <NUM> and a second surface <NUM> opposite to each other and a side surface <NUM> connecting the first surface <NUM> and the second surface <NUM>, the first surface <NUM> is away from the base plate <NUM>, and the second surface <NUM> faces the base plate <NUM>. The first surface <NUM> includes a central region <NUM> and a peripheral region <NUM> surrounding the center region <NUM>.

For a technical solution that the functional layer <NUM> is formed earlier than the first packaging layer <NUM>, there may mainly be the following examples:.

With further reference to <FIG>, after the functional layer <NUM> is formed, the cell string <NUM> may be coated around with the material for the first packaging layer <NUM> on the base plate <NUM> to form the first packaging layer <NUM>.

It shall be noted that before the first packaging layer <NUM> is formed, a second packaging layer <NUM> may be formed on the base plate <NUM>. In particular, the second packaging layer <NUM> is laid on the cell string <NUM>, and the second packaging layer <NUM> shall completely cover the cell string <NUM> and the functional layer <NUM>.

In a fourth implementation, with reference to <FIG>, the second packaging layer <NUM> is formed on the first surface of the cell string <NUM>. The functional layer <NUM> is formed around the cell string <NUM> and the second packaging layer <NUM> on the base plate <NUM>. The first packaging layer <NUM> is formed around the functional layer <NUM> on the base plate <NUM>.

In a fifth implementation, with reference to <FIG>, the surface of the cell string <NUM> is coated with the functional layer <NUM>, and the first packaging layer <NUM> is formed around the functional layer <NUM> on the base plate <NUM>. That is, the functional layer <NUM> fills a space formed by the first packaging layer <NUM>.

Example Two: with reference to <FIG>, the first packaging layer <NUM> is formed earlier than the functional layer <NUM>.

In a first implementation, with reference to <FIG>, the first packaging layer <NUM> is first formed around the cell string <NUM> on the base plate <NUM>, and partial inner wall surface of the first packaging layer <NUM> facing the cell string <NUM> on the base plate <NUM> is coated, i.e., only partial inner wall bordering with the base plate <NUM> is coated. Then the inner wall bordering with the cover plate <NUM> is coated to form the functional layer <NUM>.

In a second implementation, with reference to <FIG>, the first packaging layer <NUM> is formed around the cell string <NUM> on the base plate <NUM>, and then the inner surface of the first packaging layer <NUM> facing the cell sting <NUM> is coated to form the functional layer <NUM>.

It may be appreciated that before the first packaging layer <NUM> is formed, the second packaging layer <NUM> may further be laid on the base plate <NUM>, the second packaging layer <NUM> covering the cell string <NUM> completely.

At step S402, the cover plate <NUM> is placed on the cell string <NUM>, so that the cover plate <NUM>, the base plate <NUM> and the first packaging layer <NUM> define a sealed space, the functional layer <NUM> is located within the sealed space.

A lamination temperature shall not be higher than <NUM>, for which reasons are: firstly, high-temperature resistance of perovskite is poor; secondly, the material for the functional layer <NUM> may be affected by a high temperature, resulting in cross linking, thereby degrading performance of moisture absorption. Therefore, a lamination temperature under <NUM> would ensure that performances of perovskite and the functional layer <NUM> are not damaged.

It may be appreciated that a packaging temperature may be determined according to particular materials for the first packaging layer <NUM>, the second packaging layer <NUM> and the functional layer <NUM>.

To sum up, in this embodiment, steps of forming the first packaging layer <NUM>, the second packaging layer <NUM> and the functional layer <NUM> may be adjusted according to particular positions of the first packaging layer <NUM> and the functional layer <NUM>, so that the functional layer <NUM> is located within a sealed space defined by the first packaging layer <NUM>, the cover plate <NUM> and the base plate <NUM>, ensuring that the functional layer <NUM> is converted to a solidified layer after absorbing moisture, thereby improving packaging effect of the photovoltaic module.

A fifth embodiment of the present disclosure provides a photovoltaic module substantially identical with the photovoltaic module provided in the previous embodiments, but a main difference lies in: in the fifth embodiment, because the functional layer is converted into a solidified layer after absorbing moisture, the photovoltaic module has a solidified layer rather than a functional layer. It may be appreciated that limitation on the position of the functional layer in the previous embodiments also applies to the solidified layer. A limitation on a particular position of the solidified layer is not stated in detail in the following to avoid repetition. In the following, the photovoltaic module provided in the fifth embodiment of the present disclosure is described with reference to the drawings.

With reference to <FIG>, in this embodiment, the photovoltaic module includes: a base plate <NUM>, a cell string <NUM> and a cover plate <NUM> stacked in order; a first packaging layer <NUM> located between the base plate <NUM> and the cover plate <NUM> and surrounding the cell string <NUM>, the first packaging layer <NUM>, the base plate <NUM> and the cover plate <NUM> defining a third sealed space <NUM>; and a solidified layer <NUM> located within the third sealed space <NUM>. A material for the solidified layer <NUM> may be a material converted from a hydrolyzable and crosslinkable material after absorbing moisture.

For particular description on the base plate <NUM>, the cell string <NUM>, the cover plate <NUM> and the first packing layer <NUM>, the previous embodiments may be referred to and is not repeated here.

Herein, the solidified layer <NUM> is at least located between the first packing layer <NUM> and the cell string <NUM>. For a particular position of the solidified layer <NUM>, the limitation on the position of the functional layer in the previous embodiments also applies to the solidified layer <NUM>.

In particular, the material for the solidified layer <NUM> may either be a material converted from a hydrolyzable and crosslinkable material after absorbing moisture, or a hydrolyzable and crosslinkable material. In addition, degrees of cross linking vary in different regions of the solidified layer <NUM>. For example, a degree of cross linking of the solidified layer <NUM> facing the cover plate and the first packaging layer <NUM> is greater than that of a region facing the cell string <NUM>. The degrees of cross linking of the solidified layer <NUM> may alternatively be identical in different regions.

In the photovoltaic module, the solidified layer <NUM> may serve as a second packaging function on the cell string <NUM>, which is advantageous for further improving tightness of the cell string.

A sixth embodiment of the present disclosure provides a photovoltaic module. With reference to <FIG>, the photovoltaic module includes: a base plate <NUM>, a cell string <NUM> and a cover plate <NUM> stacked in order; a first packaging layer <NUM> located between the base plate <NUM> and the cover plate <NUM> and surrounding the cell string <NUM>, the first packaging layer <NUM>, the base plate <NUM> and the cover plate <NUM> defining a first sealed space; a moisture detection layer <NUM> located in the first sealed space. It is detected and determined whether there is moisture in the first sealed space through response information of the moisture detection layer <NUM>.

In this embodiment, the base plate <NUM> may be a conductive substrate, and the cell string <NUM> may be a string of perovskite solar cell. That is, in this embodiment, the base plate <NUM> can not only bear the cell string <NUM>, but also can serve as an anode to collect electrons generated by the cell string <NUM> after light exposure. The base plate <NUM> may be fluorine-doped tin oxide conductive glass or indium tin oxide conductive glass. That is, the base plate <NUM> may be taken as conductive glass of the cell string <NUM>.

It may be appreciated that the cell string <NUM> is of a cell structure formed by a plurality of solar cells connected in parallel or in series.

The first packaging layer <NUM> may be located between the base plate <NUM> and the cover plate <NUM>, surrounding the cell string <NUM>. The first packaging layer <NUM>, the base plate <NUM> and the cover plate <NUM> define a first sealed space.

With reference to <FIG> and <FIG>, in this embodiment, the first sealed space may be further filled with a second packaging layer <NUM>.

The response information of the moisture detection layer <NUM> may be color information or photoelectrical information. The color information is taken as an example. The response information includes a first response information and a second response information. The first response information is that color remains unchanged. The second response information is that color changes. If there is no moisture in the first sealed space, the moisture detection layer <NUM> sends out or displays the first response information. If a problem that packaging is not tight or a material ages occurs to the first packaging layer <NUM> or the second packaging layer <NUM>, moisture enters the first sealed space, and the moisture detection layer sends out or displays the second response information. Therefore, an operator may determine whether there is moisture in the first sealed space according to the response information of the moisture detection layer <NUM>. If there is moisture, the photovoltaic module is re-packaged, thereby preventing the cell string <NUM> from being decomposed or ceasing to be effective in moisture.

The moisture detection layer <NUM> is further adaptive to locate a position where the moisture is located in the first sealed space. In particular, the moisture detection layer <NUM> may be arranged in different positions of the first sealed space, and the positions of the moisture may be located according to detection results at different positions of the moisture detection layer <NUM>.

In this embodiment, the moisture detection layer <NUM> includes a moisture absorption color changeable layer. The moisture absorption color changeable layer changes its color after absorbing moisture. According to the change state of color, it may be determined whether there is moisture in the first sealed space. In addition, a particular position of the moisture may be determined according to a particular position of color change of the moisture absorption color changeable layer. Materials for the moisture absorption color changeable layer may be: copper sulfate, cobalt chloride, methylene amines or organic phenols. Take copper sulfate for example, the copper sulfate is grey-white before absorbing water, but is blue after absorbing water. Therefore, when the moisture absorption color changeable layer changes from white to blue, the operator may determine that there is moisture in the first sealed space and perform re-packaging on the photovoltaic module.

In another embodiment, the moisture detection layer <NUM> may further be a moisture-sensitive resistor or a moisture-sensitive sensor. Resistance of the moisture-sensitive resistor may change after absorbing moisture, and based on the change, it may be determined whether there is moisture in the first sealed space. The moisture-sensitive sensor may convert humidity to a signal to be sent out. Based on the signal, it may be determined whether there is moisture in the first sealed space. In addition, a plurality of moisture-sensitive resistors or moisture-sensitive sensors may be arranged in the first sealed space as separated from each other. A particular position of the moisture may be determined in regard to resistance value changes of the moisture-sensitive resistors or signal changes of the moisture-sensitive sensors in different positions.

Technical solutions for particular positions of the moisture detection layer <NUM> in the first sealed space, the following examples are mainly included:.

The separation layer <NUM> can further improve tightness of the package, and the separation layer <NUM> can also separate the moisture detection layer <NUM> from the cell string <NUM>. If the material used for the moisture detection layer <NUM> may react with the material for the cell string <NUM>, the separation layer <NUM> can prevent the moisture detection layer <NUM> from having an adverse effect on the cell string <NUM> and improve life of the cell string <NUM>. A material for the separation layer <NUM> may be an EVA film.

Example Three: Example Three: with reference to <FIG>, the moisture detection layer <NUM> is further located on the first surface <NUM> of the central region <NUM>. That is, the moisture detection layer <NUM> is located on the side surface <NUM> and the first surface <NUM> of the cell string <NUM>. A separation layer <NUM> is further included between the moisture detection layer <NUM> and the cell string <NUM>. It may be appreciated that the moisture detection layer <NUM> can further be directly attached to the side surface <NUM> and the first surface <NUM> of the cell string <NUM>, that is, there is no separation layer <NUM> between the moisture detection layer <NUM> and the cell string <NUM>.

Example Four: with reference to <FIG>, the moisture detection layer <NUM> is arranged around the cell string <NUM>, and the moisture detection layer <NUM>, the base plate <NUM> and the cover <NUM> define a second sealed space. That is, the moisture detection layer <NUM> is arranged around the side surface <NUM> of the cell string <NUM> and encloses the cell string <NUM> in the second sealed space.

The moisture detection layer <NUM> may be arranged close to a side surface of the cell string <NUM>, or there may be a gap between the moisture detection layer <NUM> and the side surface of the cell string <NUM>; or there may be a separation layer between the moisture detection layer <NUM> and the side surface <NUM> of the cell string <NUM>.

Example Five: with reference to <FIG>, there are corner junction regions between the first packaging layer <NUM> and the base plate <NUM>, and between the first packaging layer <NUM> and the cover plate <NUM>, and the moisture detection layer <NUM> is located at least in the corner junction regions. That is, the moisture detection layer <NUM> covers a boundary between the first packaging layer <NUM> and the cover plate <NUM> and the base plate <NUM>.

Example Six: with reference to <FIG>, the moisture detection layer <NUM> is further located on an inner wall surface of the first packaging layer <NUM> facing the cell string <NUM>.

Example Seven: with reference to <FIG>, the moisture detection layer <NUM> fills the first sealed space. At this time, the moisture detection layer <NUM> completely covers the cell string <NUM>, and the moisture detection layer <NUM> has a great thickness and can perform sealing well.

It shall be noted that in the Examples One to Seven, the moisture detection layer <NUM> is at least located between the first packaging layer <NUM> and the cell string <NUM>. If the first packaging layer <NUM> or the second packaging layer <NUM> is not packaged tightly or their packaging ages, a position between the first packaging layer <NUM> and the cell string <NUM> is the first position where moisture enters. Therefore, by arranging the moisture detection layer <NUM> between the first packaging layer <NUM> and the cell string <NUM>, a speed of moisture detection can be increased.

Example Eight: with reference to <FIG>, the moisture detection layer <NUM> is located between the cell string <NUM> and the cover plate <NUM>.

Example Nine: with reference to <FIG>, there are a plurality of separated moisture detection layers <NUM> in the first sealed space, and each of the moisture detection layers <NUM> is a moisture detection point. Therefore, by detecting moisture through a color change of each moisture detection point, a position of the moisture may be accurately determined.

To sum up, there is a moisture detection layer <NUM> in the first sealed space of the photovoltaic module in this embodiment. It is detected and determined whether there is moisture in the first sealed space through response information of the moisture detection layer <NUM>. In addition, the moisture detection layer <NUM> may locate a particular position of the moisture in the first sealed space. Therefore, the operator may perform re-packaging on the photovoltaic module according to the response information of the moisture detection layer <NUM>, thereby preventing the cell string <NUM> from being decomposed and ceasing to work.

A seventh embodiment of the present disclosure provides a photovoltaic module substantially identical with the photovoltaic module provided in the sixth embodiment, but differs in that in this embodiment, a base plate is a bearing board and a cell string is a string of perovskite solar cell. In this embodiment, the sixth embodiment may be referred to for portions identical or similar to the photovoltaic module provided in the six embodiment, and content of the portions is not repeated. <FIG> are schematic diagrams showing structures of a photovoltaic module provided in this embodiment.

With reference to <FIG>, the photovoltaic module includes: a base plate <NUM>, a cell string <NUM> and a cover plate <NUM> stacked in order; a first packaging layer <NUM> located between the base plate <NUM> and the cover plate <NUM> and surrounding the cell string <NUM>, the first packaging layer <NUM>, the base plate <NUM> and the cover plate <NUM> defining a first sealed space; a moisture detection layer <NUM> located in the first sealed space. It is detected and determined whether there is moisture in the first sealed space through response information of the moisture detection layer <NUM>.

In this embodiment, the base plate <NUM> is a bearing board and the cell string <NUM> is a string of perovskite solar cell. That is, the base plate <NUM> is adaptive to bear a cell string but does not have a function of collecting electrons. The base plate <NUM> may be glass or transparent plastic.

It may be appreciated that the cell string <NUM> may be directly placed on the base plate <NUM>; or that there may be a moisture detection layer and/or a second packaging layer between the cell string <NUM> and the base plate <NUM>.

For technical solutions about a particular position of the moisture detection layer <NUM> in the first sealed space, the following examples are mainly included:.

To sum up, the base plate <NUM> of the photovoltaic module provided in this embodiment is a bearing board. A second packaging layer <NUM> may be provided between the bearing board and the cell string <NUM> to improve the tightness of the package. The moisture detection layer <NUM> may be arranged between the bearing board and the cell string <NUM>, so as to locate moisture here, thereby prompting an operator to perform re-packaging on the photovoltaic module.

An eighth embodiment of the present disclosure provides a photovoltaic module substantially identical with the photovoltaic module provided in the sixth embodiment and the seventh embodiment. The photovoltaic module includes: a base plate, a cover plate, a cell string, a first packaging layer, a second packaging layer and a moisture detection layer. A main difference between this embodiment and previous embodiments lies in that the photovoltaic module provided in this embodiment includes a functional layer. For identical or similar portions of the photovoltaic module between this embodiment and the sixth and seventh embodiments, the sixth and seventh embodiments may be referred to and the content is not repeated here. <FIG> are schematic diagrams showing structures of a photovoltaic module provided this embodiment.

With reference to <FIG>, a base plate <NUM> of a conductive substrate is taken as an example. It may be appreciated that the base plate <NUM> may be a bearing board. There is no limitation to a base plate in this embodiment.

A functional layer <NUM> is located within a sealed space. The functional layer <NUM> is adaptive to absorb moisture in the sealed space and be converted into a solidified layer having a degree of cross linking greater than a degree of cross linking of the functional layer. If either the first packaging layer <NUM> or the second packaging layer <NUM> is not packaged adequately or has aged material, the functional layer <NUM> may absorb moisture and be converted into a solidified layer. That is, the functional layer <NUM> may perform packaging on the cell string <NUM> for a second time, thereby preventing the cell string <NUM> from being decomposed or ceasing to be effective in moisture.

The degree of cross linking is further called cross linking index or cross linking density, and may be used to represent a degree of cross linking of a molecular chain. In particular, the degree of cross linking refers to a fraction taken by a cross-linked structural unit of an entire structural unit. The degree of cross linking is proportional with the amount of cross link bonds: the greater the degree of cross linking, the more cross link bonds in a unit volume and the greater the cross linking density.

In this embodiment, a material for the functional layer <NUM> may be a hydrolyzable and crosslinkable material that can absorb moisture entering into the sealed space and that may have a cross-linking reaction after absorbing moisture. In this way, viscosity and compactness of the material are increased, and the second packaging may be performed.

In addition, it shall further be noted that the functional layer <NUM> absorbs moisture in the sealed space and is converted into a solidified layer, including: a partial region of the functional layer <NUM> absorbs moisture to be converted into a solidified layer. Alternatively, all of the functional layer <NUM> absorbs moisture to be converted into a solidified layer.

For technical solutions about a particular position of the functional layer <NUM> in the sealed space, the following examples are mainly included:.

It may be appreciated that the functional layer <NUM> may further be located at another position in the sealed space, and this embodiment does not put a limitation to a position of the functional layer <NUM>.

To sum up, the functional layer <NUM> provided in this embodiment has a functional layer <NUM> capable of absorbing moisture in the sealed space and being converted into a solidified layer after absorption to block moisture from entering the cell string <NUM>, thereby implementing a second packaging. In addition, there is the moisture detection layer <NUM> in the sealed space. The moisture detection layer <NUM> can detect and locate a particular position of moisture to facilitate an operator performing re-packaging on the photovoltaic module.

A ninth embodiment of the present disclosure provides a manufacturing method for a photovoltaic module. <FIG> is a flowchart showing a manufacturing method of a photovoltaic module provided in this embodiment of the present disclosure.

With reference to <FIG> and <FIG>, at step S900, the base plate <NUM>, the cell string <NUM> and the cover plate <NUM> are provided. The cell string <NUM> is stacked on the base plate <NUM>.

In this embodiment, the base plate <NUM> may be a conductive substrate, the cell string <NUM> is a perovskite solar cell film layer, and the cell string <NUM> is attached to the surface of the base plate <NUM>.

In another embodiment, a base plate <NUM> may be a bearing board, a cell string <NUM> may be a string of perovskite solar cell, and the cell string includes a conductive base plate and a perovskite solar cell film layer. The cell string may be attached to the base plate, or a functional layer and/or second packaging layer may be arranged between the cell string and the base plate.

It shall be noted that manufacturing of a photovoltaic module shall be performed in inert gas to prevent moisture in the outside from damaging the cell string.

At step S901, the first packaging layer <NUM> is formed on the base plate <NUM> and around the cell string <NUM>, and the moisture detection layer <NUM> is formed on the base plate <NUM>.

A height of the first packaging layer <NUM> is higher than a height of the cell string <NUM> to guarantee that the cell string <NUM> is in a space completely sealed after the cover plate <NUM> is placed.

In this embodiment, the moisture detection layer <NUM> is a moisture absorption color changeable layer. In another embodiment, a moisture detection layer may be a moisture-sensitive resistor or a moisture-sensitive sensor.

It may be appreciated that an order of forming the first packaging layer <NUM> and the moisture detection layer <NUM> is not fixed, but need to be adjusted according to a particular position arranged for the moisture detection layer <NUM>.

For a technical solution for forming the first packaging layer <NUM> and the moisture detection layer <NUM>, there may mainly be the following examples:
Example One: with reference to <FIG> and <FIG>, the moisture detection layer <NUM> is formed earlier than the first packaging layer <NUM>.

For a technical solution that the moisture detection layer <NUM> is formed earlier than the first packaging layer <NUM>, there may mainly be the following examples:.

With further reference to <FIG>, after the moisture detection layer <NUM> is formed, the cell string <NUM> may be coated around with the material for the first packaging layer <NUM> on the base plate <NUM> to form the first packaging layer <NUM>.

It shall be noted that before the first packaging layer <NUM> is formed, a second packaging layer <NUM> may be formed on the base plate <NUM>. In particular, the second packaging layer <NUM> is laid on the cell string <NUM>, and the second packaging layer <NUM> shall completely cover the cell string <NUM> and the moisture detection layer <NUM>.

In a fourth implementation, with reference to <FIG>, the second packaging layer <NUM> is formed on the first surface of the cell string <NUM>. The moisture detection layer <NUM> is formed around the cell string <NUM> and the second packaging layer <NUM> on the base plate <NUM>. The first packaging layer <NUM> is formed around the moisture detection layer <NUM> on the base plate <NUM>.

In a fifth implementation, with reference to <FIG>, the surface of the cell string <NUM> is coated with the moisture detection layer <NUM>, and the first packaging layer <NUM> is formed around the moisture detection layer <NUM> on the base plate <NUM>. That is, the moisture detection layer <NUM> fills a space formed by the first packaging layer <NUM>.

In a sixth implementation, with reference to <FIG>, the surface of the cell string <NUM> is covered with the second packaging layer <NUM>, the moisture detection layer <NUM> is formed on an upper surface of the second packaging layer <NUM>, and the first packaging layer <NUM> is formed around the second packaging layer <NUM> and the moisture detection layer <NUM> on the base plate <NUM>.

In a seventh implementation, with reference to <FIG>, separated moisture detection layers <NUM> are arranged on the base plate <NUM> and on the surface of the cell string <NUM>. After the moisture detection layer <NUM> is formed, the first packaging layer <NUM> is formed around the second packaging layer <NUM> and the moisture detection layer <NUM> on the base plate <NUM>.

Example Two, with reference to <FIG> and <FIG>, the first packaging layer <NUM> is formed earlier than the moisture detection layer <NUM>.

In a first implementation, with reference to <FIG>, the first packaging layer <NUM> is first formed around the cell string <NUM> on the base plate <NUM>, and partial inner wall surface of the first packaging layer <NUM> facing the cell string <NUM> on the base plate <NUM> is coated, i.e., only partial inner wall bordering with the base plate <NUM> is coated. Then the inner wall bordering with the cover plate <NUM> is coated to form the moisture detection layer <NUM>.

In a second implementation, with reference to <FIG>, the first packaging layer <NUM> is formed around the cell string <NUM> on the base plate <NUM>, and then the inner surface of the first packaging layer <NUM> facing the cell sting <NUM> is coated to form the moisture detection layer <NUM>.

At step S902, the cover plate <NUM> is placed on the cell string <NUM>, so that the cover plate <NUM>, the base plate <NUM> and the first packaging layer <NUM> define a sealed space, the moisture detection layer <NUM> is located within the sealed space.

Because high-temperature resistance of perovskite is poor, a lamination temperature shall not be higher than <NUM>.

It may be appreciated that a packaging temperature may be determined according to particular materials for the first packaging layer <NUM>, the second packaging layer <NUM> and the moisture detection layer <NUM>.

To sum up, in this embodiment, steps of forming the first packaging layer <NUM>, the second packaging layer <NUM> and the functional layer <NUM> may be adjusted according to particular positions of the first packaging layer <NUM> and the functional layer <NUM>, so that the functional layer <NUM> is located within a sealed space defined by the first packaging layer <NUM>, the cover plate <NUM> and the base plate <NUM>, and ensuring that the functional layer <NUM> can detect and locate moisture in the sealed space.

Claim 1:
A photovoltaic module comprising:
a base plate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
a cell string (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) disposed on the base plate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), the cell string (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) having a first surface facing away from the base plate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), a second surface opposite to the first surface and facing the base plate, and a side surface between the first and second surfaces;
a cover plate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) over the first surface of the cell string (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
a first packaging layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), located between the base plate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and the cover plate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and surrounding and facing the side surface of the cell string (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), wherein the first packaging layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), the base plate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and the cover plate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) define a first sealed space housing the cell string;
a plurality of moisture detection layers (<NUM>), arranged in the first sealed space and spaced from each other, wherein the plurality of moisture detection layers (<NUM>) are arranged on and across the first surface of the cell string (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and between the cell string (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and the first packaging layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), and the plurality of moisture detection layers (<NUM>) are adaptive to provide response information indicating whether there is moisture in the first sealed space; and
a second packaging layer (<NUM>) filling the first sealed space thereby embedding the cell string (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and the plurality of moisture detection layers (<NUM>), wherein a material of the second packaging layer is same as a material of the first packaging layer.