CN207852690U - A kind of back electrode for the BSF crystal silicon cells increasing Al-BSF area - Google Patents

Abstract

The utility model discloses a kind of back electrodes for the BSF crystal silicon cells increasing Al-BSF area, including the first Al-BSF area, second Al-BSF area and back electrode of the equidistantly distributed in the first Al-BSF area, the surrounding in the second Al-BSF is arranged in the back electrode, and second Al-BSF is located at back electrode and is formed by the rectangular box of intermediate hollow out.BSF crystal silicon cells made by the utility model convert benefit by increasing the area of the Al-BSF in back electrode to improve breaking current and electric current.

Description

A kind of back electrode for the BSF crystal silicon cells increasing Al-BSF area

Technical field

A kind of the utility model solar battery structure field, and in particular to BSF crystalline silicon electricity increasing Al-BSF area The back electrode in pond.

Background technology

Traditional BSF crystal silicon batteries are that aluminium penetrates into boron-doped P-type silicon originally in cell backside printing aluminium paste, sintering The P+ layers for forming one layer of several microns thick are used as back surface field, improve the open-circuit voltage Voc of battery to reduce back surface recombination velocity, together When close smooth BSF layers can increase internal reflection, raising open-circuit voltage and short circuit current.

Traditional back metal scheme is that the rectangle silver paste of certain area is first printed in silicon chip back side, is then carried on the back in silicon chip Silver-colored back electrode printing whole face aluminium paste is avoided in face, forms Al-BSF.As efficiency requirements are higher and higher, the Edge Distance silicon of Al-BSF The edge of piece is more and more closer.

When Edge Distance is smaller and smaller, the probability that silicon chip edge adheres to aluminium paste can be increasing, and the leakage current of battery also can Increasing, the area for how increasing Al-BSF has become bottleneck.Therefore the utility model devises a kind of increase Al-BSF face The electrode of long-pending BSF crystal silicon cells.

Utility model content

In view of the above-mentioned problems, the utility model proposes a kind of back electrodes for the BSF crystal silicon cells increasing Al-BSF area.

It realizes above-mentioned technical purpose, reaches above-mentioned technique effect, the utility model is achieved through the following technical solutions：

A kind of back electrode for the BSF crystal silicon cells increasing Al-BSF area, including：

First Al-BSF area；

Second Al-BSF area is distributed at equal intervals in the first Al-BSF area；

And the surrounding in the second Al-BSF is arranged in back electrode, the back electrode, second Al-BSF is located at back of the body electricity Pole is formed by the rectangular box of intermediate hollow out.

The first Al-BSF area and the second Al-BSF area use aluminium paste system as a further improvement of the utility model, Make, including the BSF layers of embedded silicon wafer layer and the aluminium electrode layer above silicon wafer layer.

The back electrode is between the first Al-BSF and the second Al-BSF as a further improvement of the utility model, Aluminium electrode layer gap in.

The width of the back electrode is 0.1-0.4mm as a further improvement of the utility model,.

The height of the back electrode is greater than or equal to the height of aluminium electrode layer as a further improvement of the utility model, Degree is 5-25um.

The back electrode and the second Al-BSF are formed by the top in region as a further improvement of the utility model, Equipped with busbar, the busbar and back electrode are to contacting.

The beneficial effects of the utility model：BSF crystal silicon cells made by the utility model are by increasing in back electrode The area of Al-BSF convert benefit to improve breaking current and electric current.

Description of the drawings

Fig. 1 is a kind of planar structure schematic diagram of embodiment of the utility model；

Fig. 2 is a kind of dimensional structure diagram of embodiment of the utility model；

Fig. 3 is a kind of prepared improvement battery figure compared with the current-voltage of conventional batteries of the utility model；

Wherein：The first Al-BSFs of 1- area, the second Al-BSFs of 2- area, 3- back electrodes, 4- busbars.

Specific implementation mode

In order to make the purpose of the utility model, technical solutions and advantages more clearly understood, with reference to embodiments, to this Utility model is further elaborated.It should be appreciated that specific embodiment described herein is only used to explain this practicality It is novel, it is not used to limit the utility model.

The application principle of the utility model is explained in detail below in conjunction with the accompanying drawings.

The back electrode structure of BSF crystal silicon cells designed by the utility model as shown in Figs. 1-2, including the first aluminium back of the body Place 1 is distributed in the second Al-BSF area 2 in the first Al-BSF area 1 at equal intervals；With back electrode 3, the back electrode 3 is set The surrounding in the second Al-BSF is set, second Al-BSF is located at back electrode 3 and is formed by the rectangular box of intermediate hollow out.

In order to prepare the back electrode of BSF crystal silicon cells as described above, the making step of the electrode includes：

The rectangular box of intermediate hollow out, the width of final prepared back electrode are printed with silver paste on the silicon chip of cell backside Degree control is highly 5-25um in 0.1-0.4mm.

Al-BSF is printed in the region that back electrode is then avoided at the back side of battery with aluminium paste, and printed Al-BSF includes position The second Al-BSF area 2 in the intermediate void region of 3 formed rectangular box of back electrode and first outside rectangular box Al-BSF area 1.It is formed by the BSF layers and the aluminium above silicon wafer layer that Al-BSF includes embedded silicon wafer layer after drying calcining Electrode layer.In the gap of aluminium electrode layer of the back electrode 3 between the first Al-BSF and the second Al-BSF, by with two The Al-BSF area of side is in contact derived current.The width control of back electrode is formed by 0.1-0.4mm, is greater than or equal to aluminium electricity The height of pole layer is 5-25um.

It welds the top that the final method using welding is formed by region in the back electrode 3 and the second Al-BSF area 2 Connect busbar 4.The busbar 4 is in contact with back electrode 3.

In order to which the height and welding pulling force, the silver paste of the making back electrode 3 described in the utility model that improve back electrode 3 are adopted It is the silver paste of high-content of the silver content more than 80%.

Using the increased Al-BSF area of monolithic battery piece in the back electrode of the BSF crystal silicon cells of the utility model making About 350-400mm², the electricity conversion of made solar cell improves 0.05-0.15%.Fig. 3 is Al-BSF face The increased 375mm of product²When prepared solar cell i-v curve, according to i-v curve statistics data such as Shown in table one.

Table one：

Pmpp is maximum service rating in table one, and Uoc is open-circuit voltage, and Isc is short circuit current, and Rs and Rsh are respectively to go here and there Connection and parallel resistance, FF are fill factor, and Eta is electricity conversion.

As shown in Table 1, the pressure of opening of the solar battery sheet prepared by the utility model increases 2mV, and short stream increases 10mA, Transfer efficiency improves 0.11%.

The advantages of basic principles and main features and the utility model of the utility model have been shown and described above.One's own profession The technical staff of industry is it should be appreciated that the present utility model is not limited to the above embodiments, described in above embodiments and description Only illustrate the principles of the present invention, on the premise of not departing from the spirit and scope of the utility model, the utility model is also It will have various changes and improvements, these various changes and improvements fall within the scope of the claimed invention.The utility model Claimed range is defined by the appending claims and its equivalent thereof.

Claims (6)

1. a kind of back electrode for the BSF crystal silicon cells increasing Al-BSF area, it is characterised in that：Including

First Al-BSF area；

Second Al-BSF area is distributed at equal intervals in the first Al-BSF area；

And the surrounding in the second Al-BSF is arranged in back electrode, the back electrode, second Al-BSF is located at back electrode institute In the rectangular box of the intermediate hollow out of formation.

2. a kind of back electrode of BSF crystal silicon cells increasing Al-BSF area according to claim 1, feature exist In：The first Al-BSF area and the second Al-BSF area is made of aluminium paste, including is embedded in the BSF layers of silicon wafer layer and is located at silicon Aluminium electrode layer above lamella.

3. a kind of back electrode of BSF crystal silicon cells increasing Al-BSF area according to claim 1 or 2, feature It is：In the gap of aluminium electrode layer of the back electrode between the first Al-BSF and the second Al-BSF.

4. a kind of back electrode of BSF crystal silicon cells increasing Al-BSF area according to claim 3, feature exist In：The width of the back electrode is 0.1-0.4mm.

5. a kind of back electrode of BSF crystal silicon cells increasing Al-BSF area according to claim 3, feature exist In：The height of the back electrode is greater than or equal to the height of aluminium electrode layer, is 5-25um.

6. a kind of back electrode of BSF crystal silicon cells increasing Al-BSF area according to claim 1, feature exist In：The top that the back electrode and the second Al-BSF is formed by region is equipped with busbar, the busbar and back electrode To contact.