CN106876486B - String formation connection structure, component and the method for P-type crystal silicon back contacts double-side cell - Google Patents

Abstract

The invention provides a string connection structure, assembly and method of a P-type crystalline silicon back-contact double-sided battery, which includes at least two battery slices, and the back of the battery slices is arranged with a positive current guide bar and a negative electrode current guide bar at intervals. The positive current guide bar is connected to the positive fine grid lines on the back of each row, and the negative electrode current guide bar is connected to multiple silver electrodes with via holes in each column. The positive electrode current guide bar and the negative electrode current guide bar are electrically insulated from each other; The battery strings are connected in series with the negative current-conducting strips through conductive connecting strips; or the positive-electrode current-conducting strips and the negative-electrode current-conducting strips of the cells are collected in the positive-electrode current collecting strips and negative-electrode current-collecting strips on the opposite side of the battery, respectively, to form interdigitated Shaped electrode structure, the positive current collecting strips and the negative current collecting strips of adjacent cells are connected in series through conductive connecting strips to form a battery string. The invention greatly enhances the degree of fusion with the existing component packaging process, improves the conversion efficiency of the component, and simplifies the process.

Description

String connection structure, component and method of P-type crystalline silicon back-contact double-sided battery

technical field

The invention belongs to the technical field of solar cells, and in particular relates to a string connection structure, component and method of a P-type crystalline silicon back-contact double-sided cell.

Background technique

At present, crystalline silicon solar cells account for more than 90% of the global market for solar cells, and the conversion efficiency of crystalline silicon cell production lines has exceeded 21%. The cost of electricity continues to shrink and is expected to be flat in the next few years. As a clean energy source, crystalline silicon solar cells play an increasingly important role in changing the energy structure and alleviating environmental pressure.

Crystalline silicon cell modules are the core terminal units of photovoltaic power generation, and their conversion efficiency and cost will greatly affect the economic benefits of photovoltaic power plants. Due to the mature production process and low manufacturing cost, P-type crystalline silicon battery components still occupy the vast majority of the market share at present and for a long period of time in the future.

If P-type crystalline silicon solar cell components want to continue to maintain competitiveness and achieve greater development and application, the conversion efficiency must be further improved while reducing production costs. The most effective way is to continuously improve the conversion efficiency of crystalline silicon cells. For example, the introduction of MWT technology into P-type crystalline silicon double-sided PERC cells can not only reduce the light-shielding area on the front of the cell, but also prevent leakage after electrode winding through the passivation film on the back. However, the series connection of P-type back-contact double-sided cells usually requires the use of conductive backplanes and conductive adhesives, which requires additional processes such as dispensing, EVA drilling, and alignment. The process requirements and production costs are relatively high. Component encapsulation devices are less compatible.

Contents of the invention

The object of the present invention is to provide a string connection structure, assembly and method of P-type crystalline silicon back-contact double-sided batteries, and connect adjacent batteries through current guide strips, current collection strips and conductive connection strips to form battery strings . While meeting the packaging requirements of P-type crystalline silicon back-contact double-sided cells, it greatly enhances the integration with the existing component packaging process, improves the conversion efficiency of the component, simplifies the process, and reduces the production cost.

In order to achieve the above object, the preparation technical scheme that the present invention adopts is:

A string connection structure of a P-type crystalline silicon back-contact double-sided battery, comprising at least two P-type crystalline silicon back-contact double-sided battery sheets, the back of the battery sheet is arranged with a positive electrode current guide bar and a negative electrode current guide bar at intervals, The positive current guide bar is connected to the positive fine grid lines on the back of each row, the negative electrode current guide bar is connected to multiple via electrodes in each column, and the positive electrode current guide bar and the negative electrode current guide bar are electrically insulated from each other;

The positive current guide strips and the negative current guide strips of adjacent cells are connected in series through conductive connecting strips to form a battery string; The negative current collecting strips form a finger-shaped electrode structure, and the positive current collecting strips and the negative current collecting strips of adjacent battery sheets are connected in series through conductive connecting strips to form a battery string.

The P-type crystalline silicon back-contact double-sided solar cell sequentially includes from the front to the back: a front negative fine grid line, a front anti-reflection film, a front passivation film, an N-type doped layer, a P-type crystalline silicon substrate, a first The back passivation film, the second back passivation film and the back positive electrode thin grid line; the front negative electrode fine grid line arranged on the front of the battery collects electrons and guides them into the negative electrode current guide strip on the back through the through-hole electrode penetrating the battery sheet; the battery The back positive fine grid lines and the back positive main grid lines are distributed in the area other than the via electrode, and the holes collected on the back of the battery are guided into the positive current guide bar on the back.

The positive electrode fine grid lines on the back side are one or more groups of parallel segments, the length is 10-80mm, the width is 30-300um, and the distance between two adjacent rows of segments is 1-4mm.

Each set of positive electrode fine grid lines on the back intersects at least one positive electrode current guiding strip, and the width of a single positive electrode current guiding strip is 0.5-5mm.

The positive current guiding strip is the positive main grid line on the back side or a conductive connecting strip bonded on the main grid line; Conductive connection strips on each column of via electrodes.

The conductive connecting strips are welding strips, reflective welding strips or transparent conductive strips; the positive current collecting strips and negative current collecting strips are welding strips, reflective welding strips, transparent conductive strips or the extension structure of positive and negative main grids.

The positive electrode current guiding strip and the negative electrode current guiding strip are parallel to each other, and the positive electrode current guiding strip and the back positive electrode fine grid line are perpendicular to each other.

The battery sheet is a whole P-type single/polycrystalline battery, or a P-type single/multi-crystalline battery after being sliced.

A photovoltaic module for double-sided power generation, including the string connection structure of the P-type crystalline silicon back-contact double-sided cells. The photovoltaic module is sequentially laminated with a light-transmitting material, a front-side encapsulation film, and a string connection structure from the front to the back. structure, the back packaging film, and the lower light-transmitting material; in the string connection structure, a reflective structure is provided on the front side of the conductive connection strip between adjacent cells.

A method for manufacturing a double-sided photovoltaic module comprising the following steps:

1) Make a positive current guide bar on the back positive busbar on the back of the P-type crystalline silicon back-contact double-sided battery, and make a negative current guide bar on each column of via electrodes; make the positive current guide bar and the negative electrode current guide bar Extending to the end of the battery sheet, or making the positive current collector strip and the negative electrode current collector strip respectively converge on the positive electrode current collection strip and the negative electrode current collection strip on the opposite side of the battery sheet, forming an interdigitated electrode structure;

2) Use conductive connecting strips to connect the positive and negative current collector strips of adjacent batteries in series to form a battery string; or use conductive connecting strips to connect the positive current collection strips and negative current collection strips of adjacent batteries in series to form a battery string ;

3) Stack layers in the order of upper light-transmitting material, encapsulating film, battery string, encapsulating film, and lower light-transmitting material;

4) laminating the stack formed in step 3) in a laminator, so that the encapsulation film is cross-linked, and the battery string and the light-transmitting material are combined into a whole;

5) After trimming, framing, and installing a junction box, a photovoltaic module for double-sided power generation is formed.

Compared with the prior art, the present invention has the following benefits:

The string connection structure of the present invention connects the positive fine grid line on the back through the positive current guiding strip, and the negative current guiding strip connects the through-hole silver electrode, and the positive and negative current guiding strips are electrically insulated from each other; The battery strings are formed by connecting with conductive connecting strips; or the positive and negative current conducting strips of the battery sheets are respectively collected in the corresponding current collecting strips on opposite sides of the battery sheets, and then connected by conductive connecting strips 13 to form battery strings. This connection structure simplifies the complicated problem of the cell connection process caused by the winding of the front electrode. While meeting the packaging requirements of P-type crystalline silicon back-contact double-sided cells, it greatly enhances the integration with the existing component packaging process, improves the conversion efficiency of the component, simplifies the process, and reduces the production cost.

Further, the P-type crystalline silicon back-contact double-sided battery sheet of the present invention introduces the front electrode winding technology into the back passivation battery technology, so that the two high-efficiency crystalline silicon battery technologies are well combined, and its effect is obviously better than that of a single use one of its techniques. By reducing the light-shielding area of the front electrode of the battery, the front of the battery is improved; at the same time, the passivation film on the back of the battery solves the leakage problem in the metal winding. In addition, the local aluminum electrodes on the back of the battery are changed to aluminum fine grid lines, so that the battery has the function of generating electricity on both sides.

The photovoltaic module structure of the present invention, by adopting the above-mentioned string connection structure, makes the integration degree of the whole module packaging process, improves the conversion efficiency of the module, simplifies the process, and reduces the production cost.

Description of drawings

Figure 1 is a partial cross-sectional schematic diagram of a P-type crystalline silicon back-contact double-sided battery along the direction of the rear positive busbar;

Fig. 2 is a schematic diagram of the interdigitated back electrode structure formed by the guide strip and the collection strip;

Fig. 3 is a schematic diagram of the battery sheet connection of the fork-shaped electrode structure;

Fig. 4 is a schematic diagram of positive and negative current guide strips on the back that are parallel to each other and distributed at equal intervals;

Fig. 5 is a schematic diagram of a straight line connection of parallel guide strips;

Fig. 6 is a schematic diagram of a P-type crystalline silicon back-contact bifacial cell connection assembly.

Among them, 1 is the anti-reflection film, 2 is the front passivation film, 3 is the N-type film, 4 is the P-type substrate, 5 is the back passivation film, 6 is the back passivation film, 7 is the back positive electrode fine grid line, 8 is a via electrode, 9 is a negative current collection strip, 10 is a positive current guide strip, 11 is a negative current guide strip, 12 is a positive current collection strip, 13 is a conductive connection strip, 14-1 is an upper light-transmitting material, 14- 2 is the lower light-transmitting material, 15 is a light-reflecting structure, and 16 is an encapsulation adhesive film.

Detailed ways

As shown in Figure 1, a string connection structure of a P-type crystalline silicon back-contact double-sided battery according to the present invention, the structural features of the battery are as follows: The P-type double-sided crystalline silicon battery includes from the front to the back: grid line, anti-reflection film 1, front passivation film 2, N-type doped layer 3, P-type crystalline silicon substrate 4, back passivation film 5, back positive fine grid line 7, back positive busbar, back negative overpass Hole electrodes 8 and busbars. The positive and negative fine grid lines on the front of the battery collect electrons and lead them into the negative main grid line on the back through the via electrode 8; the passivation film on the back isolates the positive and negative electrodes on the back of the battery well to avoid leakage; The lines are distributed in the non-via-hole electrode area, and the holes collected on the back of the battery are introduced into the positive busbar on the back. The positive electrode fine grid lines on the back are one or more sets of parallel segments, the length is 10-80mm, the width is 30-300um, and the distance between two adjacent segments is 1-4mm.

Each set of rear positive fine grid lines perpendicularly intersects at least one rear positive main grid line, the number of rear positive main grid lines is 3-15, and the width of a single rear positive main grid line is 0.5-5 mm.

As shown in Fig. 2 to Fig. 5, according to the pattern of the back electrode, the negative electrode current guide bar 11 and the positive electrode current guide bar 10 of the battery are arranged in parallel at intervals on the back of the battery, and the electrical insulation is maintained between them. The positive current guide bar 10 and the negative electrode current guide bar 11 of adjacent battery sheets are connected by conductive connecting strips 13 to form a battery string; The corresponding current collection strips 12 and 9 form interdigitated electrode structures, and the positive current collection strips and negative current collection strips of adjacent battery sheets are connected together through conductive connecting strips 13 to form a battery string.

The invention discloses a method for connecting strings of P-type crystalline silicon back-contact double-sided batteries, the specific steps of which are as follows:

(1) Make a positive electrode bus bar 10 on the back positive busbar line on the back of the P-type crystalline silicon back-contact double-sided battery, and make a negative electrode current bar 11 on each column of via electrodes 8; or, P-type crystalline silicon The positive electrode current collector strip 10 and the negative electrode current collector strip 11 on the back of the back-contact double-sided battery are respectively collected in the current collection strips (the negative electrode current collection strip 9 and the positive electrode current collection strip 12) on the opposite side of the battery sheet, forming a finger-like electrode structure , as shown in Figure 2 to Figure 5.

The positive current guiding strip 10 is a back positive busbar or a conductive connecting strip bonded to the busbar;

The negative current guide strip 11 is a negative busbar connected to each column of via electrodes or a conductive connecting strip bonded to each column of via electrodes;

The conductive connecting strip 13 is an ordinary welding strip, a reflective welding strip or a transparent conductive strip, and the width of the conductive connecting strip is 0.5-5 mm;

The current collecting strips 9 and 12 are ordinary welding strips, reflective welding strips, transparent conductive strips or the extension structure of the positive and negative busbars, and the width of the current collecting strips is 0.5-5mm;

The battery sheet is a whole piece of P-type single/polycrystalline battery standard in the industry, or a non-whole piece of P-type single/multi-crystalline battery after fragmentation;

(2) Connect the positive electrode current collector bar 10 of the adjacent battery with the negative electrode current conductor bar 11 with the conductive connecting strip 13 to form a battery string; or connect the positive electrode current collecting strip 12 of the adjacent battery with the negative electrode The current collecting bars 9 are connected to form a battery string.

(3) As shown in FIG. 6 , stack layers in the order of upper light-transmitting material 14 - 1 , encapsulating film 16 , battery string, encapsulating film 16 , and lower light-transmitting material 14 - 2 .

The light-transmitting material is ultra-clear tempered glass, light-transmitting organic material;

The encapsulation film 16 is EVA, PVB, POE or the like.

(4) Laminate the stack formed in step (3) in a laminator to cross-link the encapsulating adhesive film, and combine the battery string and the light-transmitting materials on the front and back as a whole.

(5) After trimming, framing, and junction box installation, a photovoltaic module that can be used for double-sided power generation is formed.

Example 1:

(1) Make a positive electrode reflective ribbon with a width of 1.5mm on the positive silver busbar on the back of the entire P-type monocrystalline silicon back-contact double-sided battery; make a negative electrode with a width of 1.5mm on each row of via-hole silver electrodes Reflective ribbon. The positive and negative reflective ribbons of adjacent battery slices are connected to connect the battery slices into a battery string.

(2) Laminate in the order of ultra-clear tempered glass, EVA, battery string, EVA, and ultra-clear tempered glass.

(3) Laminate the stack formed in step (2) in a laminator to cross-link the EVA, and combine the battery string and the ultra-clear tempered glass on the front and back as a whole.

(4) After processing such as trimming, framing, and junction box installation, a photovoltaic module that can be used for double-sided power generation is formed.

Example 2:

(1) During the electrode fabrication process of the battery sheet, a 2mm-wide positive electrode extension structure is provided on the back positive busbar, which is located on the side close to the edge of the silicon wafer and perpendicularly intersects with the back positive busbar; The hole electrodes are connected by silver grid lines, and form a negative electrode extension structure with a width of 2 mm on the other side of the edge of the silicon wafer, and the extension structure vertically intersects with the silver grid lines on the via hole electrodes. The positive and negative electrode extension structures are oppositely arranged on the back of the battery.

(2) Coating solder paste on the positive and negative extension structures of the battery, and combining the positive and negative extension structures of adjacent batteries through a 3mm wide copper strip to form a battery string.

(3) Laminate in the order of ultra-clear tempered glass, PVB, battery string, PVB, and ultra-clear tempered glass.

(4) Laminate the stack formed in step (2) in a laminator to cross-link the PVB, and combine the battery string and the ultra-clear tempered glass on the front and back as a whole.

(5) After trimming, framing, and junction box installation, a photovoltaic module that can be used for double-sided power generation is formed.

The above are only preferred embodiments of the present invention, and are not limited to the implementation scope of the present invention. All equivalent changes and modifications made according to the content of the patent scope of the present invention shall fall within the technical scope of the present invention.

Claims (8)

1. a kind of string formation connection structure of P-type crystal silicon back contacts double-side cell, which is characterized in that including at least two p-types crystalline substance Body silicon back contacts double-side cell piece, the cell back face interval are placed with positive flow guide bar (10) and cathode flow guide bar (11), just The often capable just superfine grid line (7) in the back side of pole flow guide bar (10) connection, cathode flow guide bar (11) connect multiple vias electricity of each row Pole (8), positive flow guide bar (10) and cathode flow guide bar (11) electrically insulated from one another；

The positive flow guide bar (10) of adjacent cell piece connects to form battery with cathode flow guide bar (11) by conductive connecting strap (13) String formation；Or the positive flow guide bar (10) of cell piece comes together in the positive electrode current of cell piece opposite side with cathode flow guide bar (11) respectively It collects item (12) and cathodal current collects item (9), form fourchette shape electrode structure, the positive electric current collection item of adjacent cell piece (12) item (9) is collected with cathodal current to connect to form battery string formation by conductive connecting strap (13)；

The P-type crystal silicon back contacts double-side cell piece includes successively by front to the back side：The thin grid line of front cathode, front subtract Reflectance coating (1), front passivating film (2), n-type doping layer (3), p-type crystal silicon matrix (4), the first backside passivation film (5), second back of the body The just superfine grid line (7) of face passivating film (6) and the back side；The thin grid line of front cathode of battery front side arrangement collects electronics, and by wearing The cathode flow guide bar (11) of saturating cell piece crossed pore electrod (8) and import the back side；The just superfine grid line (7) in the back side of cell backside and the back of the body Face anode main gate line was distributed in the region other than pore electrod (8), and the hole that cell backside is collected imports the positive water conservancy diversion at the back side Item (10)；The pore electrod (8) of crossing is arranged in the through-hole in P-type wafer, and through-hole penetrates through entire P-type silicon in thickness direction Piece, through-hole wall are n-type doping layer (3).

2. the string formation connection structure of P-type crystal silicon back contacts double-side cell according to claim 1, which is characterized in that institute The just superfine grid line (7) in the back side stated be one or more groups of line segments being mutually parallel, length be 10~80mm, width be 30~ The spacing of 300um, adjacent rows line segment are 1~4mm；

The just superfine grid line (7) in the back side described in each group is intersected at least one positive flow guide bar (10), single anode flow guide bar (10) width is 0.5~5mm.

3. the string formation connection structure of P-type crystal silicon back contacts double-side cell according to claim 1, which is characterized in that institute The positive flow guide bar (10) stated is back side anode main gate line or the conductive connecting strap being bonded in the back side anode main gate line；Institute The cathode flow guide bar (11) stated is each back side cathode main gate line for arranging pore electrod of connection or is bonded in each row via Conductive connecting strap on electrode (8).

4. the string formation connection structure of P-type crystal silicon back contacts double-side cell according to claim 1, which is characterized in that institute The conductive connecting strap (13) stated is welding or electrically conducting transparent item；The anode electric current collection item (12) is the back side anode main grid Extended structure, welding or the electrically conducting transparent item of line；The cathodal current collects the extension that item (9) is the back side cathode main gate line Structure, welding or electrically conducting transparent item.

5. the string formation connection structure of P-type crystal silicon back contacts double-side cell according to claim 1, which is characterized in that institute The positive flow guide bar (10) and the cathode flow guide bar (11) stated are mutually parallel, and the anode flow guide bar (10) and the back side are just Superfine grid line (7) is mutually perpendicular to.

6. the string formation connection structure of P-type crystal silicon back contacts double-side cell according to claim 1, which is characterized in that institute The cell piece stated is p type single crystal silicon battery/p-type polysilicon after full wafer p type single crystal silicon battery or p-type polysilicon battery or fragment Battery.

7. a kind of photovoltaic module of generating electricity on two sides, which is characterized in that including P-type crystal according to any one of claims 1 to 6 The string formation connection structure of silicon back contacts double-side cell, photovoltaic module by translucent material (14-1) on front to the back side successively lamination, Front packaging adhesive film, string formation connection structure, back side packaging adhesive film, lower translucent material (14-2)；In string formation connection structure, adjacent electricity Conductive connecting strap (13) front setting reflective structure (15) between the piece of pond.

8. the production method of the photovoltaic module of the generating electricity on two sides described in claim 7, which is characterized in that include the following steps：

1) positive flow guide bar (10) is made in the back side anode main gate line at the P-type crystal silicon back contacts double-side cell back side, and Cathode flow guide bar (11) was made on pore electrod (8) in each arranged；So that positive flow guide bar (10) is prolonged with cathode flow guide bar (11) The end of cell piece is extended to, or positive flow guide bar (10) is made to come together in cell back respectively with cathode flow guide bar (11) and face The positive electric current collection item (12) on side and cathodal current collect item (9), form fourchette shape electrode structure；

2) the positive flow guide bar (10) of adjacent cell is connected to form battery with cathode flow guide bar (11) with conductive connecting strap (13) String formation；Or the positive electric current collection item (12) of adjacent cell is collected into item (9) with cathodal current with conductive connecting strap (13) and is connected Form battery string formation；

3) by upper translucent material, the sequence lamination of packaging adhesive film, battery string formation, packaging adhesive film, lower translucent material；

4) being stacked in laminating machine for step 3) formation is subjected to lamination treatment, so that packaging adhesive film is crosslinked, by battery string formation It is integrated into a whole with translucent material；

5) through chamfered edge, frame up, install terminal box processing, formed for generating electricity on two sides photovoltaic module.