CN109949966A - A kind of high reliability PERC crystal silicon solar batteries back side conductive silver slurry and its preparation process - Google Patents

Abstract

The invention discloses a kind of high reliability PERC crystal silicon solar batteries back side conductive silver slurry and its preparation processes, slurry viscosity is 20~80PaS, it is made of following mass percentage, it includes: inorganic additive 0.1%~0.3%, glass powder 1%~5%, silver powder 45%~65%, ethyl cellulose 2%~6%, terpinol 1%~5%, decylene glycol ester 20%~35%, appropriate organic additive, wherein, glass powder is mixed by glass powder one, glass powder two.Carrier is obtained by being uniformly mixed under organic additive, ethyl cellulose, terpinol, decylene glycol ester water bath condition；Hybrid glass system, inorganic assistant are added on carrier and be uniformly mixed；Silver powder system is added on to step 2 system is uniformly mixed, rolling filtering is to get to back side conductive silver paste.The back side PERC of the present invention silver paste ensure that traditional contactless silver paste characteristic, alumina passivation layer injury is few, and due to using hybrid glass system, back side silver paste sintered electrode soldering reliability is high, under conditions of practical burning temperature is 740 DEG C~780 DEG C, there is splendid comprehensive performance.

Description

A kind of high reliability PERC crystal silicon solar batteries back side conductive silver slurry and its preparation Technique

Technical field

The present invention relates to the PERC crystal silicon battery back side electrocondution slurry preparation processes, in particular to a kind of high reliability PERC Crystal silicon solar batteries back side conductive silver slurry, belongs to solar cell preparation technology.

Background technique

With human society industrial expansion, the energy consumed by the mankind is more and more.Sun energy storage capacity is the abundantest, takes Not to the utmost, be the permanent energy and pollution-free, great effect, the benefit of solar energy played for development environment friendly society With the emphasis for having become various countries' research.In recent years, crystal silicon solar energy battery generating efficiency improved year by year, among these, PERC electricity Chi Yiqi high-photoelectric transformation efficiency obtains industry and widely pays close attention to.

PERC battery has one layer of AlOx passivating structure compared to the conventional crystalline silion cell back side, needs to be added laser in technique and opens Slot technique realizes effective electrical contact of back aluminium and silicon substrate.Meanwhile in order to protect passivation layer, PERC battery is needed sintering temperature Reduce by 30~50 DEG C.Therefore, new requirement is proposed to back side silver paste, first, back electrode silver paste need to protect during the sintering process it is blunt Change layer not to be destroyed；Second, for the stability for guaranteeing component for long periods work, back electrode need to have reliable welding performance.

PERC cell backside silver paste includes silver powder solid conduction phase, and glass powder is bonded phase, organic carrier and inorganic additive. Glass powder is as bonding phase, although proportion very little, only about accounts for 1~5%, its effect played is most important 's.Traditional crown glass system is used extensively due to relatively weak corrosivity in PERC back electrode silver paste, but it is warm to sintering Degree is sensitive, it is difficult to adapt to low-temperature sintering demand；And flint glass system preparation PERC carry on the back silver electrode, due to melt flow compared with It is good, even if fine and close silver thick film back electrode can be obtained, but still there is the insufficient defect of reliability.

Summary of the invention

Strong, more difficult to control in view of flint glass system corrosivity, crown glass corrosivity is mild, and traditional PERC carries on the back silver-colored system Single crown glass is generally selected to make bonding mutually to obtain preferable electrical property.With battery low-temperature sintering, crown glass High temperature viscosity height, poor fluidity, sintering aids role are limited and burn the defect of warm window narrows and gradually expose, and are increasingly difficult to adapt to The requirement of PERC battery low fever's temperature highback electrode reliability.

The technical problem to be solved by the embodiment of the invention is that providing a kind of high reliability PERC crystal silicon solar batteries Back side conductive silver slurry and its preparation process, the technique improve the densification of electrodes conduct network for PERC cell backside silver paste Property, soldering reliability, improve solar cell photoelectric transformation efficiency.

To achieve the above object, the technical scheme is that including following components, by percentage to the quality:

The fineness of the back side conductive silver slurry is less than 10um, and viscosity is in 20~80PaS.

Further setting is that the glass powder is mixed by glass powder one, glass powder two, two kinds of glass powder average grain diameters For 0.4~3.5um, glass powder one is crown glass system, by CuO, MgO, BaO, Al₂O₃、Bi₂O₃、Na₂O、SiO₂、Al₂O₃、 MnO₂、WO₃、B₂O₃In at least four compositions；Glass powder two is flint glass system, by ZnO, PbO, MgO, CaO, SiO₂、 Al₂O₃、TiO₂、Al₂O₃、B₂O₃、Li₂O、Bi₂O₃、Na₂At least four composition in O.

Further setting is the mixing mass ratio of glass powder one and glass powder two in 0.1~20 interval range.

It includes nano-ZnO, nanometer CuO, nanometer glass putty, nano-MgO, nanometer that further setting, which is the inorganic assistant, SiO₂, nano Co₂O₃One or more；

It is 2.0~4.5g/cm that further setting, which is silver powder tap density,³, partial size is 0.2 μm~5 μm.

It mainly includes coupling agent, thixotropic agent and dispersing agent etc. that further setting, which is organic additive, with the technique for adjusting slurry Performance.

The present invention also provides a kind of preparation processes of back side conductive silver slurry, comprising the following steps:

Step 1: by high-speed stirred 1.5 under 80 DEG C of ethyl cellulose, terpinol, decylene glycol ester, organic additive water bath conditions ~3h is uniformly mixed and obtains carrier；

Step 2: being added on the homogeneous carrier in step 1 for glass powder, inorganic assistant, is uniformly mixed；

Step 3: silver powder system is added on that step 2 system is uniformly mixed, rolling filtering is to get to back side conductive silver slurry.

Innovation Mechanism and beneficial effect of the invention is:

By the present invention in that leaded mixing crown glass system is used to carry on the back silver bonding phase as PERC, help to overcome glass powder One i.e. crown glass system sintering temperature is high, burns the defect of warm window narrows, is the addition of flint glass by glass powder two, helps In the mobility for improving glass metal, electrode is promoted to form fine and close conductive network, reduce cell series resistance, improves battery filling The factor；On the other hand it can be that flint glass powder adds content and flint glass characteristic is modulated by control glass powder two, change The mechanical strength of kind electrode and substrate contact, and then reliable contact can be obtained under the conditions of low-temperature sintering.In addition, the present invention is logical It crosses and the reliability that inorganic additive significantly improves rear electrode is added.

In conclusion operation of the present invention is simple, easy to implement, the silver electrode of the back electrode silver paste sintering of preparation can improve electricity The compactness and soldering reliability of pole conductive network improve PERC battery comprehensive performance.

Detailed description of the invention

In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this Some embodiments of invention, for those of ordinary skill in the art, without any creative labor, according to These attached drawings obtain other attached drawings and still fall within scope of the invention.

Fig. 1 is PERC battery schematic diagram；

Fig. 2 is that back electrode is sintered outside drawing.

Specific embodiment

To make the object, technical solutions and advantages of the present invention clearer, the present invention is made into one below in conjunction with attached drawing Step ground detailed description.

Examples 1 to 5: a kind of high reliability PERC crystal silicon solar batteries back side conductive silver slurry, the back silver are led Plasma-based material forms quality such as table one:

Table one

The glass powder composition is respectively as follows:

One molar fraction group of glass powder becomes 0.1~0.2 part of Bi₂O₃, 0.01~0.2 part of Na₂O, 0.1~0.3 part of CuO, 0.05~0.2 part of Al₂O₃, 0.35~0.55 part of SiO₂, 0~0.2 part of MnO₂；

Two molar fraction of glass powder forms 0.2~0.4 part of PbO, 0.2~0.5 part of SiO₂, 0.01~0.1 part of Li₂O、0.02 ~0.3 part of Al₂O₃, 0.1~0.15 part of TiO₂, 0.05~0.2 part of B₂O₃；

Described to implement one~implementation five, inorganic assistant is nanometer CuO, nanometer glass putty, Nano-meter SiO_2₂It is one or more Combination；

Silver powder conductive phase average grain diameter is between 0.2~3um, 2.0~4.5g/cm3 of tap density；

Above-mentioned PERC crystal silicon solar batteries rear electrode conductive silver paste production technology is as follows:

Step 1, high-speed stirred 1.5 under 80 DEG C of ethyl cellulose, terpinol, decylene glycol ester, organic additive water bath conditions~ 3h is uniformly mixed and obtains carrier；

Hybrid glass system, inorganic assistant are added on the homogeneous carrier in step 1 by step 2, are uniformly mixed；

Step 3, silver powder system are added on step 2 system and are uniformly mixed, roll five times, filter to get back side conductive silver is arrived Slurry；

Step 4 is screen-printed to the monocrystalline PERC piece back side using the back side the PERC conductive silver paste of invention and prepares back electrode, Electric field, positive electrode are carried on the back using currently most preferably silver paste combines, is monocrystalline PERC finished battery after 760 DEG C of cofirings.

Embodiment one tests electrical property such as table two:

Table two

PASTE	Uoc	Isc	Rs	Rsh	FF	Eff	Pulling force/N
								ref	0.6611	9.591	0.00273	69.59	77.43	0.2027	4.00
Implement one	0.6604	9.599	0.00268	64.93	77.56	0.2030	5.70

Embodiment two tests electrical property such as table three:

Table three

PASTE	Uoc	Isc	Rs	Rsh	FF	Eff	Pulling force/N
								ref	0.6625	9.604	0.00288	82.22	77.39	0.2031	4.40
Implement two	0.6628	9.623	0.00292	33.83	77.23	0.2033	5.20

Embodiment three tests electrical property such as table four:

Table four

PASTE	Uoc	Isc	Rs	Rsh	FF	Eff	Pulling force/N
								ref	0.6580	9.617	0.00239	14.42	79.07	0.2066	4.52
Implement three	0.6583	9.612	0.00245	25.22	79.31	0.2072	5.57

Example IV tests electrical property such as table five:

Table five

PASTE	Uoc	Isc	Rs	Rsh	FF	Eff	Pulling force/N
								ref	0.6594	9.626	0.00503	39.34	75.67	0.1983	4.52
Implement four	0.6604	9.634	0.00499	50.06	76.07	0.1998	5.02

Embodiment five tests electrical property such as table six:

Table six

PASTE	Uoc	Isc	Rs	Rsh	FF	Eff	Pulling force/N
								ref	0.6581	9.587	0.00481	49.57	75.88	0.1977	4.12
Implement five	0.6582	9.584	0.00439	37.31	76.39	0.1989	5.15

Table one, table two, table three, table four, table five illustrate that the Eff of five embodiment batteries is higher than comparative example.This explanation is mixed It closes glass system and help to obtain preferable electrical property, and obtain high welding pulling force.

The above disclosure is only the preferred embodiments of the present invention, cannot limit the right model of the present invention with this certainly It encloses, therefore equivalent changes made in accordance with the claims of the present invention, is still within the scope of the present invention.

Claims (7)

1. a kind of high reliability PERC crystal silicon solar batteries back side conductive silver slurry, it is characterised in that including following components, with Mass percent meter:

The fineness of the back side conductive silver slurry is less than 10um, and viscosity is in 20~80PaS range.

2. a kind of high reliability PERC crystal silicon solar batteries back side conductive silver slurry according to claim 1, feature Be: the glass powder is mixed by glass powder one, glass powder two, and two kinds of glass powder average grain diameters are 0.4~3.5um, glass Glass powder one is crown glass system, by CuO, MgO, BaO, Al₂O₃、Bi₂O₃、Na₂O、SiO₂、Al₂O₃、MnO₂、WO₃、B₂O₃In At least four compositions；Glass powder two is flint glass system, by ZnO, PbO, MgO, CaO, SiO₂、Al₂O₃、TiO₂、Al₂O₃、 B₂O₃、Li₂O、Bi₂O₃、Na₂At least four composition in O.

3. a kind of high reliability PERC crystal silicon solar batteries back side conductive silver slurry according to claim 2, feature Be: the mixing mass ratio of glass powder one and glass powder two is in 0.1~20 interval range.

4. a kind of high reliability PERC crystal silicon solar batteries back side conductive silver slurry according to claim 1, feature Be: the inorganic assistant includes nano-ZnO, nanometer CuO, nanometer glass putty, nano-MgO, Nano-meter SiO_2₂, nano Co₂O₃One kind Or it is several.

5. a kind of high reliability PERC crystal silicon solar batteries back side conductive silver slurry according to claim 1, feature Be: silver powder tap density is 2.0~4.5g/cm³, partial size is 0.2 μm~5 μm.

6. a kind of high reliability PERC crystal silicon solar batteries back side conductive silver slurry according to claim 1, feature Be: organic additive includes coupling agent, thixotropic agent, dispersing agent.

7. a kind of preparation process of the back side conductive silver slurry as described in one of claim 1-6, it is characterised in that including following Step:

Step 1: by high-speed stirred 1.5 under 80 DEG C of ethyl cellulose, terpinol, decylene glycol ester, organic additive water bath conditions~ 3h is uniformly mixed and obtains carrier；

Step 2: being added on the homogeneous carrier in step 1 for glass powder, inorganic assistant, is uniformly mixed；

Step 3: silver powder system is added on that step 2 system is uniformly mixed, rolling filtering is to get to back side conductive silver slurry.