CN117153918A - Packaging method for flexible solar cells with same-plane electrodes - Google Patents

Abstract

The invention discloses a packaging method for a coplanar electrode flexible solar cell, which specifically comprises the following steps: step S1, a first back packaging piece is provided, and a plurality of grooves are formed in the surface of the first back packaging piece. And filling negative film glue in the groove, and filling the back of the battery piece facing the negative film glue into the groove. Step S2, electrically connecting a plurality of battery pieces, and connecting the plurality of battery pieces in series and parallel; and step S3, providing a front packaging piece, and adhering the front packaging piece to the front surface of the battery piece by using cover plate glue. The invention changes the traditional process flow of welding and packaging the battery by utilizing the characteristics of the battery with the same surface electrode, and the first back packaging piece can provide support for the battery piece and balance the stress in the battery piece when the battery piece is welded on the front surface by packaging the back surfaces of the battery pieces, connecting the battery pieces in series and parallel and completing the front surface packaging mode of the battery piece.

Description

Packaging method for flexible solar cells with same-surface electrodes

Technical field

The invention relates to the technical field of aerospace energy systems, and in particular to a packaging method for co-planar electrode flexible solar cells.

Background technique

At present, in view of the application demand background of future space, flexible thin film gallium arsenide solar cell technology has become a research hotspot at home and abroad. Thin-film gallium arsenide solar cells not only maintain the high efficiency of gallium arsenide solar cells, but also have the advantages of being lightweight and ultra-thin, and have extremely high weight-to-power ratio. Thin-film gallium arsenide solar cells use polyimide as the cell substrate. The cell weight specific power will exceed 3000W/kg, and the curl radius can be less than 1cm. It is very suitable for being attached to space spacecraft such as micro-satellites and space probes. surface.

Along with the lightweight and high-efficiency advantages of thin-film gallium arsenide solar cells, there are two problems in the preparation process of thin-film gallium arsenide solar cell modules: ① In the preparation process of traditional battery modules, the welding of the cells is usually completed first and then Cell packaging. Since the gallium arsenide solar cell is composed of multiple layers of different materials, its internal stress is uneven and the battery is easy to bend, which affects its welding; ② As shown in Figure 1, the gallium arsenide cell sheet from the front to the negative includes Front electrode layer, active layer, and back electrode layer. Because the gallium arsenide cell sheet is thin and the distance between the front electrode and the back electrode is close, when the interconnection sheet is deformed, the interconnection sheet is prone to the phenomenon shown in Figure 1 B, that is, the interconnection sheet simultaneously Contact the front electrode and the side wall of the front electrode, causing a short circuit in the battery.

Contents of the invention

In view of the problems existing in the prior art, the present invention provides a packaging method for flexible solar cells with same-plane electrodes. Different from the traditional battery packaging process, the present invention first encapsulates the back side of the battery cells, and then completes the series and parallel connection of the battery cells and the front side packaging.

In order to achieve the above objectives, the present invention provides a packaging method for co-planar electrode flexible solar cells. The packaging method includes the following steps:

Step S1, backside packaging of the battery sheet: provide a first backside package, the surface of which is provided with a number of grooves; fill the grooves with film glue, and turn the backside of the battery sheet toward the film Glue into the groove.

Preferably, after the battery sheet is installed in the groove, a pressing block is placed on the front of the battery sheet, and the battery sheet is pressed down by the pressing block so that the battery sheet can be embedded on the surface of the negative film glue, so that the negative film glue can cover at least Part of the side wall of the battery piece.

Preferably, the front side of the battery sheet is covered with an electrostatic adsorption film; after the pressing block is removed from the battery sheet, the electrostatic adsorption film is removed from the front side of the battery sheet to expose the electrodes. to connect the battery cells in series and parallel.

Step S2, series and parallel connection of battery sheets: electrically connect several battery sheets so that several battery sheets are connected in series and parallel.

Specifically, the battery sheets are connected in series and parallel by welding or using conductive glue.

Step S3, front-side packaging of the battery sheet: provide a front-side packaging component, and use a cover sheet glue to bond the front-side packaging component to the front side of the battery sheet.

Preferably, the depth of the groove is greater than the thickness of the battery sheet.

Preferably, after the backsheet glue is cured, it covers at least part of the side wall of the battery sheet.

Preferably, the first back package is prepared by the following method:

Take the initial back package with a flat surface and use machinery or laser to directly etch grooves on the surface of the initial back package; or,

An initial back package with a flat surface is taken, a through hole is etched on the initial back package to form a second back package, and the second back package is bonded to another initial back package.

Preferably, the first back package is a back film or a back plate, and the back film is made of polyimide.

Preferably, the cover glue is silicone rubber or polyolefin glue, the front sealing member is cerium-doped glass or an ethylene-tetrafluoroethylene copolymer light-transmitting film, and the backsheet glue is silicone rubber.

Preferably, the flexible solar cell is a gallium arsenide, amorphous silicon, copper indium gallium tin, cadmium telluride, or perovskite thin film solar cell.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The present invention utilizes the characteristics of the same-surface electrode battery to change the traditional process of first welding and then packaging the battery. By first packaging the back of the battery, then connecting the battery in series and parallel, and then completing the front packaging of the battery. When the battery sheet is welded on the front, the first back package can provide support for the battery sheet, balance the stress inside the battery sheet, and prevent the battery from bending due to uneven stress.

(2) The present invention completes the packaging of the battery sheet by embedding the battery sheet into the groove, so that the side walls of the groove form protection for the side walls of the electrode layer on the back of the battery sheet. The principle is as follows:

Since the battery sheets of the present invention are embedded in the grooves, the interconnecting sheets must cross the side walls of the grooves to electrically connect two adjacent battery sheets. At this time, if the interconnecting piece is deformed and has a tendency to move toward the side wall of the back electrode layer, the side walls of the groove will block its movement toward the side wall of the back electrode layer, thereby reducing the interconnection piece from contacting the side wall of the back electrode layer and causing a battery short circuit. risks of.

(3) When the battery sheet of the present invention is packaged on the back, the negative film glue covers at least part of the side wall of the back electrode layer, and this part of the side wall is insulated by the negative film glue, even if the interconnection sheet contacts this part of the insulated side wall , there will be no battery short circuit, further reducing the risk of battery short circuit.

(4) After the negative film adhesive of the present invention and the battery sheet are installed in the groove, a pressing block is placed on the surface of the battery sheet, and the battery sheet is slightly pressed down by the pressing block. This setting is because after the negative film glue and the battery piece are installed in the groove, the battery piece is placed on the negative film glue. The pressing block slightly presses the battery piece so that the battery piece is embedded in the surface of the negative film glue, so that the negative film glue can at least cover the back electrode layer. part of the side wall.

Description of the drawings

Figure 1 is a schematic diagram of the electrical connection of existing solar cells; A in Figure 1 is a schematic diagram of the electrical connection of existing solar cells when the interconnection sheet is in a normal state; B in Figure 1 is a diagram of the existing solar cell in a deformed state of the interconnection sheet. Schematic diagram of battery cell electrical connections.

Figure 2 is a schematic flow chart of the packaging method of flexible solar cells with same-surface electrodes according to the present invention; wherein, A in Figure 2 is a schematic diagram of the state of packaging the back of the cell in the packaging method of flexible solar cells with same-surface electrodes of the present invention; Figure 2 B is a schematic diagram of the state of the front side of the cell sheet in the packaging method for flexible solar cells with same-surface electrodes of the present invention; C in Figure 2 is the state after the packaging of the cell sheet is completed in the packaging method of flexible solar cells with same-surface electrodes of the present invention. Schematic diagram.

Figure 3 is a schematic diagram of the electrical connection of adjacent battery sheets after the battery sheet packaging of the present invention is completed.

FIG. 4 is a front view of the back package after groove etching is completed according to the present invention.

FIG. 5 is a top view of the backside package after groove etching according to the present invention.

In the picture: 1-front package, 2-cover adhesive, 3-battery sheet, 4-backsheet adhesive, 5-rear package, 6-electrostatic adsorption film, 7-pressing block, 8-interconnect sheet.

Detailed ways

The technical solution of the present invention will be further described below with reference to the accompanying drawings and examples.

As shown in Figure 2, the present invention provides a packaging method for co-planar electrode flexible solar cells. The packaging method includes the following steps:

Step S1, backside packaging of cell 3:

A first back package 5 is provided, the surface of which is provided with a plurality of grooves. Fill the groove with negative film glue 4, and then put the battery sheet 3 into the groove with the back side facing the negative film glue 4.

Step S2, series and parallel connection of battery cells 3:

Several battery sheets 3 are electrically connected so that several battery sheets 3 are connected in series and parallel.

Step S3, front packaging of cell 3:

A front package 1 is provided, and the cover sheet glue 2 is used to bond the front package 1 to the front of the battery piece 3 .

The packaging method of the present invention is designed for co-planar electrode batteries. The structure of conventional solar cells from front to negative is the front electrode layer, active layer and back electrode layer. The structure of the same-surface electrode battery is different from that of conventional solar cells. The same-surface electrode battery is based on the conventional solar cell. The active layer is corroded, so that the back electrode layer is exposed from the front. The interconnection piece is connected to the front side of the back electrode layer to electrically connect the cell to other cells. Therefore, the series and parallel operation of the cell only needs to be done on the front side of the cell. Proceed head-on.

By utilizing the characteristics of the above-mentioned same-surface electrode battery, the present invention changes the traditional battery process of first welding and then packaging, by first packaging the back of the battery sheet 3, then connecting the battery sheets 3 in series and parallel, and then completing the front packaging of the battery sheet 3. , so that when the battery sheet 3 is welded on the front, the first back package 5 provides support for the battery sheet 3, balances the stress inside the battery sheet 3, and prevents the battery from bending due to uneven stress.

In addition, the present invention completes the packaging of the battery sheet by embedding the battery sheet into the groove, so that the side walls of the groove protect the side walls of the electrode layer on the back of the battery sheet. The principle is as follows:

As shown in FIG. 3 , since the battery sheet 3 of the present invention is packaged by being embedded in a groove, the interconnecting sheet 8 must cross the side walls of the groove to electrically connect two adjacent battery sheets 3 . At this time, if the interconnection piece 8 has a tendency to deform and move toward the side wall of the back electrode layer, the side walls of the groove will act as a barrier to prevent the interconnection piece 8 from moving toward the side wall of the back electrode layer, thereby reducing the occurrence of the problem as shown in Figure 1 As shown in Figure B, the interconnection sheet 8 contacts the side walls of the front electrode layer and the back electrode layer at the same time, resulting in a short circuit of the battery.

In some embodiments, the depth of the groove may be greater than the thickness of the cell sheet 3 , or may be slightly less than the thickness of the cell sheet 3 . As long as the side walls of the groove can block part of the side walls of the back electrode layer, it can hinder the flow to a certain extent. The interconnect piece 8 is in contact with the side wall of this part.

In some embodiments, the length and width of the above-mentioned groove are slightly larger than the length and width of the battery piece 3 .

Specifically, the length and width of the groove can be 0.1-0.2mm longer than the length and width of the battery piece, so that there is a smaller gap between the groove and the side wall of the back electrode layer. The smaller gap makes the interconnection piece 8 It is not easy to extend between the side wall of the groove and the side wall of the back electrode layer, thereby reducing the risk of the interconnection sheet 8 contacting the side wall of the back electrode layer.

In some embodiments, the preparation method of the first back package 5 can be selected from the following two:

The first one is to use machinery or laser to directly etch grooves on the surface of the initial back package for thicker, unetched initial back packages;

The second method is to use a thinner initial back package, first etching through holes on the initial back package to form a second back package, and then bonding the second back package to the unetched initial back package. On the package, a first back package 5 is formed.

In some embodiments, the first back package 5 may be a flexible back film or a rigid back plate.

For the same battery piece, when the front electrode and the back electrode of the battery piece are connected, the battery will be short-circuited. Therefore, in some embodiments, after the battery piece 3 is installed in the groove, a pressure is placed on the front side of the battery piece 3. Block 7, use the pressing block 7 to gently press down the battery sheet 3, so that the battery sheet 3 can be embedded on the surface of the negative film glue 4, so that the negative film glue 4 at least covers the side wall of the electrode layer on the back of the battery piece 3, even if the interconnection piece is in contact When it comes to this part of the insulated side wall, battery short circuit will not occur, further reducing the risk of battery short circuit.

In addition, since the flexible battery sheet 3 itself is easy to bend, in some embodiments, before the back side of the battery sheet 3 is packaged, the front side of the battery sheet 3 is covered with an electrostatic adsorption film 6 , and the electrostatic adsorption film 6 makes the battery sheet 3 flat in advance. , to facilitate subsequent packaging operations.

In some embodiments, the series-parallel connection of the battery cells 3 can be achieved through welding processes such as resistance welding and soldering, or through the use of conductive glue.

In some embodiments, the battery sheets 3 are connected in series and parallel through the interconnection sheets 8 , and welding bypass diodes can also be added as needed.

Example 1

The cover glue 2 and the bottom glue 4 used in this embodiment are silicone rubber, the front package 1 is cerium-doped glass, and the first back package is a polyimide back film. Cerium-doped glass has certain radiation resistance, with an optical transmittance of >92%. After irradiation of the glass, the light transmittance in the wavelength range of 500 to 1100nm decreases by approximately 0.8%.

The packaging method for flexible solar cells with same-plane electrodes provided in this embodiment is as follows:

(1) According to the required electrical performance parameters, conduct layout and series-parallel design of the cells 3. The design content includes the size of the flexible thin film solar cell module, the spacing and quantity of the grooves on the first back package, and the number of cells 3. Series and parallel forms, etc., form drawings; the flexible thin film solar cell module is a module composed of several cells connected in series and parallel and then sealed. In this embodiment, the size of the drawing is 90cm×60cm.

(2) Input the above drawings into mechanical scribing or laser etching equipment, cut the 300 μm first back package into a size of 90cm × 60cm, and according to the drawings, etch a depth of 100 μm at the position where the battery piece 3 is to be attached. , a groove with an area of 40.1mm×60.1mm, and the distance between adjacent groove edges is 0.9mm, forming a back film with a groove array arrangement as shown in Figures 4 and 5.

(3) Please refer to Figure A in Figure 2. Place the negative film adhesive 4 and the flexible thin film gallium arsenide solar cell (4cm×6cm, 65μm thick) with the electrostatic adsorption film 6 on the front side into the grooves in sequence, and place them on each Place a 75-100g pressing block 7 on the electrostatic adsorption film 6, and lightly press the battery sheet 3 to fix the battery sheet 3 and the negative film glue 4. After the negative film glue 4 solidifies, remove the surface pressure block 7 and the electrostatic adsorption film 6.

(4) According to the drawing in step (1), weld the battery slices 3 that have been packaged and fixed on the back through the interconnection sheet 8 to realize battery series and parallel connection. Welding bypass diodes can be added as needed.

(5) Please refer to Figure B in Figure 2. Apply 25μm cover glue 2 on the front of the battery that has been completely welded, and place the 65μm thick front package 1. The pressure block 7 is used to pressurize and package again. After curing, the pressure block 7 is removed to complete the front side packaging of the battery, and a thin film gallium arsenide solar cell module suitable for use in a space environment can be formed as shown in Figure 2 (C).

Example 2

The difference between this embodiment and Embodiment 1 is that in step (5), polyolefin (POE) film is used as the cover glue 2, and an ethylene-tetrafluoroethylene copolymer (ETFE) light-transmitting film is used as the front package 1. The lamination process realizes the front packaging of the battery.

To sum up, unlike the traditional battery packaging process, the present invention first completes the back packaging of the battery sheets, and then completes the series and parallel connection of the battery sheets and the front packaging. During back packaging, the present invention forms a groove on the surface of the back package, and packages the battery piece in the groove, so that the groove forms an insulating protection for the side wall of the electrode layer on the back side of the battery piece. When the interconnection piece is deformed, , blocking the interconnection sheet from moving toward the sidewall of the back electrode layer, thereby reducing the risk of the interconnection sheet contacting the sidewall of the back electrode layer and causing a battery short circuit.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as limiting the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (10)

1. The packaging method for the coplanar electrode flexible solar cell is characterized by comprising the following steps of:

step S1, packaging the back of the battery piece:

providing a first back packaging piece, wherein a plurality of grooves are formed in the surface of the first back packaging piece; filling negative film glue in the groove, and filling the back surface of the battery piece facing the negative film glue into the groove;

step S2, series-parallel connection of the battery pieces:

electrically connecting a plurality of battery pieces to enable the plurality of battery pieces to be connected in series and parallel;

step S3, packaging the front surface of the battery piece:

a front side package is provided that is adhered to the front side of the battery cell using a coverglass adhesive.

2. The packaging method for the coplanar electrode flexible solar cell as set forth in claim 1 wherein the depth of the groove is greater than the thickness of the cell sheet.

3. The packaging method for the coplanar electrode flexible solar cell according to claim 1, wherein in step S1, after the cell is mounted in the groove, a pressing block is placed on the front surface of the cell, and the cell is pressed down by the pressing block, so that the cell can be embedded on the surface of the negative film adhesive, and at least part of the side wall of the cell is covered after the negative film adhesive is solidified.

4. The packaging method for the coplanar electrode flexible solar battery as set forth in claim 3, wherein in step S1, an electrostatic adsorption film is attached to the front surface of the battery piece; and after the pressing block is removed from the battery piece, removing the electrostatic adsorption film from the front surface of the battery piece, and exposing the electrode so as to carry out series-parallel connection of the battery piece.

5. The packaging method for the coplanar electrode flexible solar battery as set forth in claim 1, wherein in step S2, the battery pieces are connected in series and parallel by welding or using conductive adhesive.

6. The packaging method for a homoplanar electrode flexible solar cell according to claim 1, wherein the first back side package is prepared by:

taking an initial back packaging piece with a flat surface, and directly etching the surface of the initial back packaging piece by using machinery or laser to form a groove; or alternatively, the first and second heat exchangers may be,

taking an initial back packaging piece with a flat surface, etching a through hole on the initial back packaging piece, and forming a second back packaging piece; and adhering the second back surface packaging piece to another initial back surface packaging piece.

7. The packaging method for a homoplanar electrode flexible solar cell according to claim 1, wherein the first back package is a back film or a back sheet, the back film being made of polyimide.

8. The packaging method for the same-side electrode flexible solar cell according to claim 1, wherein the cover sheet adhesive is silicon rubber or polyolefin adhesive, and the front-side packaging piece is cerium-doped glass or ethylene-tetrafluoroethylene copolymer light-transmitting film.

9. The packaging method for the coplanar electrode flexible solar cell as set forth in claim 1, wherein the negative film is silicone rubber.

10. The packaging method for the coplanar electrode flexible solar cell as set forth in claim 1, wherein the flexible solar cell is gallium arsenide, amorphous silicon, copper indium gallium tin, cadmium telluride, or perovskite thin film solar cell.