Background technology
Crystal silicon solar batteries is a kind of electronic devices and components that solar energy can transform into electric energy. The preparation of crystalline silicon class solaode is generally through operations such as making herbs into wool, diffusion, plated film, silk screen printing, sintering. Making herbs into wool is divided into monocrystalline, polycrystalline making herbs into wool, single crystal battery is that the method using alkali making herbs into wool forms pyramid matte at silicon chip surface, polycrystalline battery uses the method for acid etch to form pit matte at silicon chip surface, and the matte of silicon face can increase the sunlight absorption at battery surface, reaches light trapping effect; The mode that diffusing procedure is by thermal diffusion is internally formed P-N junction to silicon chip, and so when there being light to irradiate, silicon chip is internal just can form voltage, is the basis of solar cell generating; Coating process is to reduce the minority carrier compound at battery surface, it is possible to improve the conversion efficiency of crystal silicon solar cell sheet; Silkscreen process is exactly make the electrode of solaode, so just electric current can be derived when light irradiates. Silk screen printing is most widely used a kind of technique in the preparation of present crystal silicon battery, process sequence is for first carrying out backplate printing and drying, then printing and the drying of aluminum back surface field are carried out, finally carry out the printing of front electrode, drying, it is being sintered, is allowing the silver slurry preparing electrode use be formed with battery and contact.
In the front electrode of crystal silicon solar batteries, electrode structure generally includes crisscross main gate line and secondary grid line, and main gate line is electrical connected with secondary grid line. When there being illumination, cell piece will produce electric current, and electric current flows to surface electrode pair grid line through internal emitter, collects via secondary grid line and is then flowed in battery main gate line and derives. Electric current can produce loss in the process that secondary grid line is collected, and this we are known as the power loss of resistance. Battery main gate line and secondary grid line are in the sensitive surface of battery, so will necessarily block a part of light and be radiated at battery surface, thus decreasing the effective area of shining light of battery, this partial loss is we term it optical loss.Whether P type or N-type cell, as long as there is electrode structure in battery front side, it is necessary to considers continuing to optimize of electrode structure, to reach not only to reduce shading-area but also ensure the purpose that electric current is derived smoothly.
In existing electrode structure at right side, the quantity of main gate line is generally 3, and its width is about 1.5mm; The quantity of secondary grid line is generally 80~100, and its width is about 40 μm. The wider width of main gate line so that the welding of front electrode and battery can weld well, but shading-area is also bigger. In recent years, in order to reduce the shading-area of front electrode, propose in the industry a kind of electrode structure at right side without main grid, mainly 3 main gate line in electrode structure at right side are removed, only retain secondary grid line, after battery completes, superfine cylindrical welding is used directly to weld with secondary grid line, by the direct derived current of welding. Superfine welding with in the welding process of secondary grid line, the abnormal conditions causing rosin joint maybe cannot weld owing to the width grid line less, secondary of secondary grid line is too low etc., make the power of photovoltaic module reduce.
Summary of the invention
In view of the deficiency that prior art exists, the invention provides a kind of crystal silicon solar batteries, by the improvement to electrode structure at right side so that electrode structure at right side can reach not only to reduce shading-area but also ensure the purpose that electric current is derived smoothly; Further, improve the back electrode structure in this solaode accordingly, save the consumption of silver slurry in back electrode structure.
To achieve these goals, present invention employs following technical scheme:
A kind of crystal silicon solar batteries, including battery body and be positioned at the front electrode in battery body front and be positioned at the back electrode at the battery body back side, wherein, described front electrode also includes the thin grid line of M bar of spaced arrangement in a second direction, described thin grid line is electrically connected with described secondary grid line, and the width of described thin grid line is 0.10~0.25mm; Wherein, M=10~20; Wherein, each thin grid line is additionally provided with spaced N number of solder contacts, described solder contacts lamination is arranged on described thin grid line and is electrically connected with described thin grid line, it is two or more that described solder contacts is shaped in square, circular and ellipse, the length range of the minor face of the described square length of side, circular diameter or ellipse is 0.2~1mm respectively, and the length of the minor face of the described square length of side, circular diameter or ellipse is respectively greater than the width of described thin grid line; Wherein, N=5~15; Described back electrode includes N × M electrode unit, described electrode unit and described solder contacts one_to_one corresponding, and described electrode unit length in the first direction and a second direction is not less than described solder contacts length on correspondence direction respectively.
Preferably, described solder contacts is formed on described thin grid line by secondary printing technique.
Preferably, described a plurality of secondary grid line equidistantly arranges in the first direction, and the described thin grid line of M bar equidistantly arranges in a second direction, and described second direction and described first direction are mutually perpendicular to; Described solder contacts is arranged at the position that described thin grid line intersects with described secondary grid line.
Preferably, the N number of solder contacts on each thin grid line equidistantly arranges along the length direction of described thin grid line.
Preferably, all solder contacts in described front electrode are the array distribution of N row × M row.
Preferably, on each thin grid line, difform solder contacts alternate intervals is arranged.
The shape of the solder contacts being preferably located on a thin grid line is identical, and the shape of the solder contacts on adjacent two thin grid lines is different.
Preferably, described electrode unit includes spaced first electrode portion, the second electrode portion and the 3rd electrode portion in the first direction, and is going up in the first direction, and the length in described second electrode portion is respectively greater than the length in the first electrode portion and the 3rd electrode portion.
Preferably, going up in the first direction, the length ratio in described first electrode portion, the second electrode portion and the 3rd electrode portion is (0.4~0.6): 1:(0.4~0.6).
Preferably, going up in the first direction, the length in described second electrode portion is 0.6~1mm, and spaced apart between described second electrode portion and the first electrode portion and the 3rd electrode portion is 0.3~0.6mm.
Compared to prior art, in the front electrode of the crystal silicon solar batteries that the embodiment of the present invention provides, the thin grid line that the more width of usage quantity is less replaces main gate line of the prior art, shading-area is less generally, reduce light loss, and greater number of thin grid line is evenly distributed on solar battery front side so that the electric current that secondary grid line is collected can more successfully be derived, and reduces power attenuation; It addition, be provided with, at thin grid line superimposed layer, square, the circular or oval solder contacts that area is bigger, add the contact area of pad and the height of pad, when welding welding, the problem that less welding is abnormal with welding of battery film. Further, back electrode is divided into and solder contacts electrode unit one to one, and electrode unit adopts stagewise, effectively reduce the consumption of silver slurry in back electrode structure.
Detailed description of the invention
For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in detail. The example of these preferred implementations has illustrated in the accompanying drawings. Shown in accompanying drawing and the embodiments of the present invention that describe with reference to the accompanying drawings merely exemplary, and the present invention is not limited to these embodiments.
At this, in addition it is also necessary to explanation, in order to avoid having obscured the present invention because of unnecessary details, illustrate only in the accompanying drawings and according to the closely-related structure of the solution of the present invention and/or process step, and eliminate other details little with relation of the present invention.
As it is shown in figure 1, the present embodiment provide firstly a kind of crystal silicon solar batteries, this crystal silicon solar batteries mainly includes battery body 1 and is positioned at the front electrode 2 in battery body 1 front and is positioned at the back electrode 3 at battery body 1 back side. Battery body 1 mainly adopts the PN junction battery that silicon chip is formed by process for etching, diffusion technique and etching technics preparation. Front electrode 2 and back electrode 3 are respectively formed in two sides of battery body 1 mainly by screen printing process, for exporting the electric energy of battery body 1 conversion.
Consult Fig. 2 and Fig. 3, front electrode 2 in the present embodiment offer includes in the first direction a plurality of secondary grid line 10 that (Y-direction in Fig. 2) is spaced and arranged in parallel, the a plurality of thin grid line 20 that (X-direction in Fig. 2) is spaced and arranged in parallel in a second direction, described a plurality of secondary grid line 10 is electrically connected with each other with described a plurality of thin grid line 20.Wherein, secondary grid line 10 is mainly used in collecting the photogenerated current that solaode produces, and thin grid line 20 is for collecting output by the electric current that secondary grid line 10 is collected. Further, each thin grid line 20 being additionally provided with spaced multiple solder contacts 30, described solder contacts 30 lamination is arranged on described thin grid line 20 and is electrically connected with described thin grid line 20, and the shape of described solder contacts 30 includes circular and square. Described solder contacts 30 is mainly used for after battery completes to be welded to connect with welding. Specific in the present embodiment, on each thin grid line 20, circular and square solder contacts 30 alternate intervals is arranged. Certainly, in some other embodiments, difform solder contacts 30 can also be arrange in any order.
Wherein, the quantity of secondary grid line 10 can select in the scope of 80~100, and its width can select in the scope of 30~50 μm. The quantity M of thin grid line 20 can select in the scope of 10~20, and its width D 1 can select in the scope of 0.10~0.25mm. The quantity N of the solder contacts 30 arranged on each thin grid line 20 can select in the scope of 5~15, the diameter R of circular solder contacts 30 can select in the scope of 0.2~1mm, and meet the diameter R width more than thin grid line 20 of solder contacts 30, the length of side L1 of square solder contacts 30 can select in the scope of 0.2~1mm, and to meet the length of side width more than thin grid line 20 of solder contacts 30. In the present embodiment, the quantity of secondary grid line 10 is 90, and the width of secondary grid line 10 is 40 μm; The quantity M=15 of thin grid line 20, the width D 1 of thin grid line 20 is 0.2mm; The quantity N=10 of the solder contacts 30 on each thin grid line 20, the diameter R of circular solder contacts 30 is 0.8mm, and square solder contacts 30 is specially square, and its length of side L1 is 0.8mm.
Wherein, described solder contacts 30 lamination is arranged on described thin grid line 20. Specifically, when preparing electrode structure at right side, first pass through one-step print technique and prepare secondary grid line 10 and thin grid line 20, then on described thin grid line 20, prepare solder contacts 30 again through secondary printing technique.
In the present embodiment, as shown in Figure 2, described a plurality of secondary grid line 10 (Y-direction in Fig. 2) in the first direction equidistantly arranges, the thin grid line 20 of described M bar (X-direction in Fig. 2) in a second direction equidistantly arranges, and described second direction and described first direction are mutually perpendicular to. Further, described solder contacts 30 is arranged at the position that described thin grid line 20 intersects with described secondary grid line 10, and, the N number of solder contacts 30 on each thin grid line 20 equidistantly arranges along the length direction of described thin grid line 20.
More specifically, in the present embodiment, as in figure 2 it is shown, the arrangement pitches of the N number of solder contacts 30 on each thin grid line 20 is all equal, therefore, in whole electrode structure at right side, all solder contacts 30 are the array distribution of N row × M row. Specifically, owing to solder contacts 30 alternate intervals circular and square on each thin grid line 20 is arranged, in the solder contacts 30 of N row × M row, the solder contacts 30 that odd number behavior is circular, the solder contacts 30 that even number behavior is square; It is of course also possible to be set to the solder contacts 30 that even number behavior is circular, the solder contacts 30 that odd number behavior is square.
Further, in some other embodiments, it is also possible to be that to arrange the shape of the solder contacts 30 on two thin grid lines 20 that the shape of solder contacts 30 being positioned on a thin grid line 20 is identical and adjacent different.Specifically, the generally circular in shape of solder contacts 30 on the thin grid line of Article 1 20 can be set, arrange the solder contacts 30 on the thin grid line of Article 2 20 be shaped as square, namely in the solder contacts 30 of N row × M row, odd number is classified as the solder contacts 30 of circle, and even number is classified as square solder contacts 30; It is of course also possible to be set to even number to be classified as the solder contacts 30 of circle, odd number is classified as square solder contacts 30.
The front electrode of the crystal silicon solar batteries that above example provides can be effectively reduced shading-area. Be of a size of the square of 156mm × 156mm for solar battery front side, the electrode structure at right side provided according to front electrode and the embodiment of the present invention of existing three main grids calculates shading-area respectively:
1, the electrode structure at right side of existing three main grids. Conventional three wide main gate line of 1.5mm, 90 40 μm of secondary grid lines structure in, main gate line may be designed as hollow out form, reduces the silver slurry that printing uses, but during welding, still can burn-on the welding about 1.5mm width and keep the sun off in all regions of main grid. Therefore the shielded area of sunlight is 1.5mm × 3 × 156mm=702mm by main grid place2; Secondary grid line and 4 frame shielded areas are 0.04mm × (90+2) × (153.5mm-1.5mm × 3)+2 × 153.5mm × 0.04mm=560.6mm2. Total shielded area of conventional three main grid front electrodes is 1262.6mm2。
2, the electrode structure at right side that the embodiment of the present invention provides. According to example specifically, the quantity of secondary grid line is 90, and its width is 40 μm; The quantity of thin grid line is 15, and its width is 0.2mm; The quantity of the solder contacts on each thin grid line is 10, and the shape half of solder contacts is circular, and its diameter R is 0.8mm, and second half is square, and its length of side is 0.8mm. Then:
The shielded area of sunlight is by a, 15 thin grid lines: 0.2mm × 15 × 156mm=468mm2;
B, secondary grid line and 4 frames blocking as 0.04mm × (90+2) × (153.5mm-0.2mm × 10)+0.04mm × 2 × 153.5mm=566.12mm sunlight2;
C, except thin grid line the circular pattern of 0.8mm diameter to sunlight block for:
[π×0.42mm2-(0.8mm-0.2mm)×0.04mm-π×0.42mm2× 29 ° × 2 ÷ 360 °-0.2 × 0.4 × sin14.5] × 75=28.32mm2;
D, except thin grid line the square pattern of the 0.8mm length of side blocking as (0.8mm-0.2mm) × 0.8mm × 75=36mm sunlight2;
Total shielded area is above: 468mm2+566.12mm2+28.32mm2+36mm2=1098.44mm2. The front electrode that the embodiment of the present invention provides is compared to the front electrode of existing three main grids, and the shading-area of its minimizing is: 1262.6mm2-1098.44mm2=164.16mm2。
In some other embodiments, with reference to front electrode as provided above, wherein solder contacts 30 can also be designed as ellipse. Namely, the shape of solder contacts 30 includes ellipse and circle, or include oval and square, it is also possible to be include simultaneously oval and circular and square, oval and circular and square on each thin grid line 20 alternate intervals arrange or arrange in any order. Specifically, oval solder contacts 30 as shown in Figure 4, oval solder contacts 30 is also disposed on the position that described thin grid line 20 intersects with described secondary grid line 10. Oval long limit is identical with thin grid line 20 bearing of trend, and oval minor face is identical with secondary grid line 10 bearing of trend. Wherein, the length of oval minor face can select in the scope of 0.2~1mm, and to meet the length L2 of minor face of solder contacts 30 more than the width D 1 of thin grid line 20.
Further, consult Fig. 5 and Fig. 6, back electrode 3 in the present embodiment includes N × M electrode unit 31, namely described electrode unit 31 is equal with the quantity of described solder contacts 30, and described electrode unit 31 and described solder contacts 30 one_to_one corresponding, the length on described electrode unit 31 (Y-direction in Fig. 5) in a first direction and second direction (X-direction in Fig. 5) be not less than respectively as described in solder contacts length on correspondence direction. Specifically, if solder contacts 30 is circular, then described electrode unit 31 length in the first direction and a second direction is not less than the diameter of the solder contacts 30 of circle respectively; If solder contacts 30 is oval, then described electrode unit 31 length in a first direction is not less than the major axis of the solder contacts 30 of ellipse, and the length in second direction is not less than the short axle of the solder contacts 30 of ellipse; If solder contacts 30 is square, described electrode unit 31 length in the first direction and a second direction is not less than the square solder contacts 30 length on correspondence direction respectively.
Wherein, as shown in Figure 6, described electrode unit 31 includes the 311, second electrode portion of spaced first electrode portion 312 and the 3rd electrode portion 313 in the first direction, and going up in the first direction, the length in described second electrode portion 312 is respectively greater than the length in the first electrode portion 311 and the 3rd electrode portion 313. In preferred scheme, going up in the first direction, the length ratio L21:L22:L23=(0.4~0.6) in the 311, second electrode portion of described first electrode portion 312 and the 3rd electrode portion 312: 1:(0.4~0.6). Wherein, the length L21 in described second electrode portion 312 can be chosen as 0.6~1mm, and between described second electrode portion 312 and the first electrode portion 311 and the 3rd electrode portion 313, D21 and D22 spaced apart can be chosen as 0.3~0.6mm. Wherein, L21 and L23 can be chosen as equal numerical value, and D21 and D22 can be chosen as equal numerical value. Specific in the present embodiment, the value of parameters is as follows: L21=L23=0.5mm, L22=1mm, D21=D22=0.5mm; Electrode unit 31 in the equal diameters of the length L24 gone up in a second direction Yu solder contacts 30, i.e. L24=0.8mm.
The back electrode of existing three main grid solaodes generally includes three row, and every string includes three electrode blocks being of a size of 21mm × 3mm, and the entire area of back electrode is: 21mm × 3mm × 9=567mm2。
In the back electrode structure that embodiments above of the present invention provides, including 10 × 15=150 electrode unit, the width of electrode unit is L24=0.8mm, and length is L21+L22+L23=2mm, and the entire area of back electrode is: 2mm × 0.8mm × 150=240mm2。
The back electrode that the embodiment of the present invention provides is compared to the back electrode of existing three main grid solaodes, and its entire area decreases 567mm2-240mm2=327mm2, when identical screen printing process, silver slurry consumption decreases more than 50%, greatly reduces cost.
In sum, in the front electrode of the crystal silicon solar batteries that above example provides, the thin grid line that the more width of usage quantity is less replaces main gate line of the prior art, shading-area is less generally, reduce light loss, and greater number of thin grid line is evenly distributed on solar battery front side so that the electric current that secondary grid line is collected can more successfully be derived, and reduces power attenuation; It addition, be provided with, at thin grid line superimposed layer, the square circular or oval solder contacts that area is bigger, add the contact area of pad and the height of pad, when welding welding, the problem that less welding is abnormal with welding of battery film. Further, back electrode is divided into and solder contacts electrode unit one to one, and electrode unit adopts stagewise, effectively reduce the consumption of silver slurry in back electrode structure.
It should be noted that, in this article, the relational terms of such as first and second or the like is used merely to separate an entity or operation with another entity or operating space, and not necessarily requires or imply the relation that there is any this reality between these entities or operation or sequentially.And, term " includes ", " comprising " or its any other variant are intended to comprising of nonexcludability, so that include the process of a series of key element, method, article or equipment not only include those key elements, but also include other key elements being not expressly set out, or also include the key element intrinsic for this process, method, article or equipment. When there is no more restriction, statement " including ... " key element limited, it is not excluded that there is also other identical element in including the process of described key element, method, article or equipment.
The above is only the detailed description of the invention of the application; it should be pointed out that, for those skilled in the art, under the premise without departing from the application principle; can also making some improvements and modifications, these improvements and modifications also should be regarded as the protection domain of the application.