Patent Description:
The white adhesive film can be used in the lower layer of the module, can achieve the purpose of increasing the power of the module by reflecting visible light and near-infrared light, and can be applied to single glass modules and double glass modules. The requirements for the appearance of the modules are rather stringent, and the white adhesive film must not overflow onto the cell sheets, bus bars and welding strips, and must not have defects such as folds.

In the prior art, the following solutions are usually adopted to solve the problem of white substance overflow of the white adhesive film:.

The technical solution to be solved by the present disclosure is to provide an encapsulation adhesive film for a solar cell that can solve the problem of overflowing of a white substance well, and a preparation method and use thereof.

To solve the above technical problems, the present disclosure employs the following technical solution:.

According to an advantageous embodiment, the encapsulation adhesive film for a solar cell further comprises a second adhesive film layer in contact with a back-sheet or a glass.

According to another embodiment,, the encapsulation adhesive film for a solar cell further comprises one or more third adhesive film layers arranged between the first adhesive film layer and the second adhesive film layer.

In the present disclosure, the first adhesive film layer, the second adhesive film layer and the transparent layer are not limited to one layer, and may be multiple layers of the same formula. The third adhesive film layer may be an adhesive film layer adopted a conventional formula.

According to a preferred embodiment of the invention, the composition of the second adhesive film layer comprises a resin and a colored filler with a mass ratio of <NUM> to <NUM>: <NUM>.

More preferably, the composition of the second adhesive film layer comprises a cross-linking agent accounting for <NUM> % to <NUM> % of the total mass of the resin and the colored filler, an auxiliary cross-linking agent accounting for <NUM> % to <NUM> % of the total mass of the resin and the colored filler, a coupling agent accounting for <NUM> % to <NUM> % of the total mass of the resin and the colored filler, and a light stabilizer accounting for <NUM> % to <NUM> % of the total mass of the resin and the colored filler.

The second adhesive film layer in the present disclosure is also a white layer, but when compared with the first adhesive film layer, the amount of white filler added is small, therefore, the second adhesive film layer can well maintain the adhesive property to the back-sheet or glass, and at the same time, the second adhesive film layer and the first adhesive film layer have a large total thickness, high reflectivity, and a large increased power.

If the thickness of the transparent layer is too thick, although it can better prevent white substance overflow, it will affect the power of the solar cell; if the transparent layer is too thin, the ability to prevent white substance overflow is limited.

In the present disclosure, due to the presence of the transparent layer, the physical properties of the adhesive film are not significantly changed by the addition of titanium dioxide or the presence of the pre-crosslinked layer, and the stripping strength from the cell sheet, the surface hardness, etc. are not significantly changed.

According to a preferred embodiment of the invention, the composition of the transparent layer comprises a resin, a cross-linking agent accounting for <NUM> % to <NUM> % of the mass of the resin, an auxiliary cross-linking agent accounting for <NUM> % to <NUM> % of the mass of the resin, a coupling agent accounting for <NUM> % to <NUM> % of the mass of the resin, and a light stabilizer accounting for <NUM> % to <NUM> % of the mass of the resin.

According to a preferred embodiment of the invention, the resin is selected from the group consisting of EVA, POE, PVB, and combinations thereof.

In the present disclosure, the resins in the first adhesive film layer, the second adhesive film layer and the transparent layer may be the same resin, or may be different resins.

According to a preferred embodiment of the invention, the photo initiator is selected from the group consisting of <NUM>-hydroxy-<NUM>-methyl-<NUM>-phenyl-<NUM>-propanon, <NUM>-hydroxycyclohexyl phenyl ketone, benzophenone, diphenyl(<NUM>,<NUM>, <NUM>-trimethylbenzoyl)phosphine oxide, <NUM>-benzyl-<NUM>-(dimethylamino)-<NUM>-(<NUM>-morpholino phenyl) butanone, <NUM>-hydroxy-<NUM>-(<NUM>-(<NUM>-hydroxy-<NUM>-methylpropionylphenyl) benzyl)-<NUM>-methyl-<NUM>-propanon, macromolecular photoinitiators thioxanthones, visible-light photo initiator camphor quinone, and combinations thereof.

In the present disclosure, the cross-linking agents in the first adhesive film layer, the second adhesive film layer and the transparent layer may be the same, or may be different.

In the present disclosure, the auxiliary cross-linking agents in the first adhesive film layer, the second adhesive film layer and the transparent layer may be the same, or may be different.

In the present disclosure, the coupling agents in the first adhesive film layer, the second adhesive film layer and the transparent layer may be the same, or may be different.

According to a preferred embodiment of the invention, the light stabilizer is selected from the group consisting of bis(<NUM>,<NUM>,<NUM>,<NUM>-tetramethyl-<NUM>-piperidyl) sebacate, poly(<NUM>-hydroxy-<NUM>,<NUM>,<NUM>,<NUM> -tetramethyl-<NUM>-piperidine ethanol-alt-<NUM>,<NUM>-butanedioic acid), poly-{[<NUM>-[(<NUM>,<NUM>,<NUM>,<NUM>-tetramethylbutyl)-imino]-<NUM>,<NUM>,<NUM>-triazine-<NUM> ,<NUM>-diyl][<NUM>-(<NUM>,<NUM>,<NUM>,<NUM>-tetramethylpiperidyl)-nitrilo]-hexamethylene-[<NUM>-(<NUM>,<NUM>,<NUM>,<NUM>-tetrame thylpiperidyl)-amino], and combinations thereof.

In the present disclosure, the light stabilizers in the first adhesive film layer, the second adhesive film layer and the transparent layer may be the same, or may be different.

Another objective of the present disclosure is to provide a preparation method of an encapsulation adhesive film for a solar cell, comprising following steps preformed successively:.

According to a preferred embodiment of the invention, Step (<NUM>) uses a co-extrusion casting machine for casting film formation.

According to a preferred embodiment of the invention, a processing temperature of Step (<NUM>) is <NUM> to <NUM>.

According to a preferred embodiment of the invention, in Step (<NUM>), after three-roll setting, cooling and winding are performed.

According to a preferred embodiment of the invention, a cooling temperature of Step (<NUM>) is <NUM> to <NUM>.

A third objective of the present disclosure is to provide use of an encapsulation adhesive film for a solar cell in a solar cell.

Due to the implementation of the above technical solutions, the present disclosure has the following advantages over the prior art:.

The present disclosure adopts a transparent layer and a first adhesive film layer, wherein the layer in contact with the cell sheet is the transparent layer, which to a certain extent blocks the white substance in the first adhesive film layer from overflowing to the cell sheet, bus bars and soldering strips, and plays a certain role in preventing white substance overflow; a photo initiator is added to the formula of the first adhesive film layer, and during the preparation process, UV light penetrates the transparent layer, reaches the first adhesive film layer, and initiates a cross-linking reaction on the surface of the first adhesive film layer, so that there is a pre-cross-linked layer on the surface of the first adhesive film layer, and the presence of this pre-cross-linked layer further effectively prevents white substance overflow.

The encapsulation adhesive film of the present disclosure has good adhesion to the cell sheet and the glass or back-sheet, high reflectivity, and a great increase in the power of the solar cell.

<FIG> is a schematic structure diagram of the present disclosure;
wherein, <NUM> - transparent layer; <NUM> - first adhesive film layer; <NUM> - second adhesive film layer.

In the following, the present disclosure is further explained in detail combining with specific embodiments, but the present disclosure is not limited to the following embodiments. The implementation conditions adopted in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are the conventional conditions in the industry. All other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protective scope of the present disclosure.

The thickness of the transparent layer <NUM> was <NUM>, and its raw materials components were, EVA: <NUM>; tert-butyl peroxy <NUM>-ethylhexyl carbonate: <NUM>; triallyl isocyanate: <NUM>; trimethylolpropane triacrylate: <NUM>; <NUM>-methacryloxypropylmethyltrimethoxysilane: <NUM>; bis(<NUM>,<NUM>,<NUM>,<NUM>-tetramethyl-<NUM>-piperidyl) sebacate: <NUM>.

The thickness of the first adhesive film layer <NUM> was <NUM>, and its raw materials components were, EVA: <NUM>; titanium dioxide: <NUM>; tert-butyl peroxy <NUM>-ethylhexyl carbonate:<NUM>; <NUM>-hydroxy-<NUM>-methyl-<NUM>-phenyl-<NUM>-propanon: <NUM>; triallyl isocyanate: <NUM>; trimethylolpropane triacrylate: <NUM>; <NUM>-methacryloxypropylmethyltrimethoxysilane: <NUM>; bis(<NUM>,<NUM>,<NUM>,<NUM>-tetramethyl-<NUM>-piperidyl) sebacate: <NUM>.

The thickness of the second adhesive film layer <NUM> was <NUM>, and its raw materials components were, EVA: <NUM>; titanium dioxide: <NUM>; tert-butyl peroxy <NUM>-ethylhexyl carbonate: <NUM>; triallyl isocyanate: <NUM>; trimethylolpropane triacrylate: <NUM>; <NUM>-methacryloxypropylmethyltrimethoxysilane: <NUM>; bis(<NUM>,<NUM>,<NUM>,<NUM>-tetramethyl-<NUM>-piperidyl) sebacate: <NUM>.

It is basically the same as Embodiment <NUM>, differing by that, the resin used in the first adhesive film layer, the second adhesive film layer, and the transparent layer was POE.

It is basically the same as Embodiment <NUM>, differing by that, the photo initiator in the first adhesive film layer was <NUM>-hydroxycyclohexyl phenyl ketone.

It is basically the same as Embodiment <NUM>, differing by that, the photo initiator in the first adhesive film layer was benzophenone.

It is basically the same as Embodiment <NUM>, differing by that, the photo initiator in the first adhesive film layer was <NUM>-hydroxy-<NUM>-(<NUM>-(<NUM>-hydroxy-<NUM>-methylpropionylphenyl) benzyl)-<NUM>-methyl-<NUM>-propanon.

It is basically the same as Embodiment <NUM>, differing by that, the photo initiator in the first adhesive film layer was <NUM>-benzyl-<NUM>-(dimethylamino)-<NUM>-(<NUM>-morpholino phenyl) butanone.

It is basically the same as Embodiment <NUM>, differing by that, the thickness of the transparent layer was <NUM>.

It is basically the same as Embodiment <NUM>, differing by that, in the raw materials of the first adhesive film layer, EVA was <NUM>; titanium dioxide was <NUM>.

It is basically the same as Embodiment <NUM>, differing by that, in the raw materials of the first adhesive film layer, the addition amount of the photo initiator was <NUM>.

It is basically the same as Embodiment <NUM>, differing by that, in the raw materials of the second adhesive film layer, EVA was <NUM>; titanium dioxide was <NUM>.

It is basically the same as Embodiment <NUM>, differing by that, the thickness of the first adhesive film layer was <NUM>, without a second adhesive film layer.

It is basically the same as Embodiment <NUM>, differing by that, a conventional third white adhesive film layer with a thickness of <NUM> was provides between the first adhesive film layer and the second adhesive film layer.

It is basically the same as Embodiment <NUM>, differing by that, in the first adhesive film layer, EVA was <NUM>; titanium dioxide was <NUM>.

The experimental data of the respective embodiments and controls are shown in Table <NUM>.

The test methods of crosslinking degree, stripping strength and reflectivity in the present disclosure refer to GB/T29848-<NUM> (Chinese standard "Ethylene-vinyl acetate copolymer (EVA) adhesive film for photovoltaic module encapsulation"). The test method of assembly power refers to IEC61215 standard.

Claim 1:
An encapsulation adhesive film for a solar cell, wherein, it comprises a transparent layer, and a first adhesive film layer in contact with the transparent layer,
the composition of the first adhesive film layer comprises following components: a resin and a colored filler with a mass ratio of <NUM> to <NUM>: <NUM>, a cross-linking agent accounting for <NUM> % to <NUM> % of the total mass of the resin and the colored filler, an auxiliary cross-linking agent accounting for <NUM> % to <NUM> % of the total mass of the resin and the colored filler, a coupling agent accounting for <NUM> % to <NUM> % of the total mass of the resin and the colored filler, a light stabilizer accounting for <NUM> % to <NUM> % of the total mass of the resin and the colored filler, and a photo initiator accounting for <NUM> % to <NUM> % of the total mass of the resin and the colored filler;
the cross-linking agent is selected from the group consisting of tert-butyl peroxy <NUM>-ethylhexyl carbonate, t-butyl peroxy-isopropyl carbonate, dibenzoyl peroxide, dicumyl peroxide, <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-bis(tert-butylperoxy)hexane, cyclohexanone peroxide, tert-butyl hydroperoxide, tert-butyl peroxybenzoate, tert-butyl peroxyacetate, di-(<NUM>-tert-butylcyclohexyl) peroxybicarbonate, tert-butyl <NUM>,<NUM>,<NUM>-trimethylperoxyhexanoate, triallyl isocyanate, and combinations thereof;
the auxiliary cross-linking agent is selected from the group consisting of trimethylolpropane triacrylate, <NUM>-trimethylolpropane tetraacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, and combinations thereof;
the coupling agent is selected from the group consisting of <NUM>-methacryloxypropylmethyltrimethoxysilane, (<NUM>-glycidylpropyl)trimethoxysilane, vinyltrimethoxysilane, <NUM>-amimopropyltriethoxysilane, and combinations thereof;
the colored filler is titanium dioxide;
a thickness of the transparent layer is <NUM> to <NUM>.