阅读说明：本技术 一种异质结电池片及其叠瓦组件的制备方法 (Preparation method of heterojunction battery piece and laminated assembly thereof ) 是由 刘云磊 欧衍聪 戴珍林 于 2021-08-17 设计创作，主要内容包括：本发明涉及的一种异质结电池片及其叠瓦组件的制备方法,一种异质结电池片及其叠瓦组件的制备方法,包括以下内容：激光切割：选取基材硅片通过激光切割成两分片或者三分片,切割深度采用60%以上的深度进行切割,然后让硅片自动裂片；清洗；非晶硅薄膜沉积；TCO导电膜制备；印刷；固化使得银栅线与TCO导电膜之间形成良好的欧姆接触；测试分档。本发明通过对工艺流程的优化,解决大尺寸异质结电池制作由于硅片翘曲导致的电池效率损失问题和减少切割带来的异质结叠瓦组件的功率损失,从而提升组件功率。(The invention relates to a preparation method of a heterojunction battery piece and a laminated assembly thereof, and the preparation method of the heterojunction battery piece and the laminated assembly thereof comprises the following contents: laser cutting: selecting a substrate silicon wafer, cutting the substrate silicon wafer into two or three sub-wafers by laser, wherein the cutting depth is over 60 percent, and then automatically cracking the silicon wafer; cleaning; depositing an amorphous silicon thin film; preparing a TCO conductive film; printing; curing to form good ohmic contact between the silver grid line and the TCO conductive film; and (6) testing and grading. According to the invention, through optimizing the process flow, the problem of battery efficiency loss caused by silicon wafer warping in large-size heterojunction battery manufacturing is solved, and the power loss of the heterojunction stack assembly caused by cutting is reduced, so that the assembly power is improved.)

1. The preparation method of the heterojunction battery piece is characterized by comprising the following steps:

laser cutting: selecting a substrate silicon wafer, cutting the substrate silicon wafer into two or three sub-wafers by laser, and breaking the silicon wafer into small wafers;

cleaning: the small pieces after cutting and splitting are subjected to wool making and cleaning treatment;

depositing an amorphous silicon thin film;

preparing a TCO conductive film;

printing: forming front and back Ag electrodes by screen printing;

and (3) curing: curing to form good ohmic contact between the silver grid line and the TCO conductive film;

testing and grading: a test of the electrical performance of the cells was conducted.

2. The method for preparing a heterojunction battery plate according to claim 1, wherein: the cutting depth during laser cutting is over 60 percent.

3. The method for preparing a heterojunction battery plate according to claim 1, wherein: when the TCO conductive film is prepared, because the mask with the width of 0.3mm-0.7mm can be generated around each unit cell due to the shielding of the carrier plate, the number of cell units is increased after the silicon wafer is divided into two or three pieces, and the number of masks is increased.

4. A method of making a stack of heterojunction battery plates as in claim 1, comprising:

step one, laser cutting:

cutting and splitting the battery piece according to the design pattern by using laser;

step two, splitting the sheet:

breaking the cut battery pieces into battery pieces according to a precut route;

step three, sorting the small pieces:

sorting the appearance of the battery pieces, selecting out bad pieces, and then loading the pieces;

step four, small conductive adhesive printing and adhesive coating:

conducting conductive adhesive printing is carried out on the sorted qualified battery slices, the printing adopts a sectional printing mode, a conductive bonding material for conducting is coated in a printing or dispensing mode, and then a bonding agent for enhancing the bonding effect is coated;

step five, overlapping the small pieces into a battery string;

welding terminals at two ends of the battery string;

step seven, typesetting and laminating the battery strings,

step eight, an assembly packaging procedure;

and step nine, connecting the junction box.

5. The method of claim 4, wherein the step of forming a stack of heterojunction cells comprises: before cutting, firstly, designing a screen printing plate of two divided batteries, wherein the two divided batteries are provided with two cutting lines according to trisection, the front of each battery is provided with three main grid lines, two side edges of each battery are respectively provided with a first main grid line and a second main grid line, a dividing line at the left part of each battery is provided with a third main grid line, the back of each battery is provided with three main grid lines, a dividing line at the right part of each battery is provided with a fourth main grid line and a fifth main grid line, the fourth main grid line and the fifth main grid line are arranged at two sides of the dividing line in a back-to-back manner, a dividing line at the left part of each battery is provided with a sixth main grid line, and the sixth main grid lines are arranged at back-to-back positions corresponding to the third main grid lines.

6. The method of claim 4, wherein the step of forming a stack of heterojunction cells comprises: before cutting in the first step, firstly, designing a screen printing plate of a three-part battery, wherein the three-part battery is provided with a cutting line according to two equal parts, two main grid lines are respectively arranged on two side edges of the front surface of the battery, and two main grid lines are arranged at the position of a dividing line of the back surface of the battery back to back.

7. The method of claim 4, wherein the step of forming a stack of heterojunction cells comprises: and step four, because the conductive adhesive is arranged on the upper surface of the battery piece, glue dispensing or other methods are needed to be adopted when the adhesive is coated, and the adhesive is coated between the conductive adhesives at intervals or between two adjacent conductive adhesives in a dispensing manner.

8. The method of claim 4, wherein the step of forming a stack of heterojunction cells comprises: and seventhly, performing circuit connection on the left six battery strings and the right six battery strings through first bus bars, respectively welding a second bus bar and a third bus bar to one end of the left six battery strings and the right six battery strings, connecting a fourth bus bar with the second bus bar, connecting a fifth bus bar with the third bus bar, and using the fourth bus bar and the fifth bus bar as the anode and cathode output ends of the assembly.

9. The method of claim 4, wherein the step of forming a stack of heterojunction cells comprises: and step nine, the junction boxes are separately designed and positioned at two ends of the assembly.

Technical Field

The invention relates to the technical field of solar cell modules, in particular to a heterojunction cell and a preparation method of a laminated tile module thereof.

Background

With the wide application of solar energy, the solar photovoltaic panel industry is also developed vigorously, and when a traditional solar cell panel is produced, due to the characteristics of the structure of the cell, a plurality of cells and welding strips need to be welded into a cell string, and then the cell string and other components are assembled into a whole. Because each cell is provided with the welding strip, the illumination area of the cell is greatly reduced, and the effective power generation area is reduced; moreover, on the battery string formed by serial connection, the distance is also formed between the battery pieces, so that the illumination area or the power generation area is also reduced; the above two causes cause a low power generation efficiency of the battery piece.

The lamination assembly adopts another battery piece interconnection technology, slices the battery piece, places one side of the battery piece A below another battery piece B after slicing, makes the main grid line electrode on the front side of the battery piece A and the main grid line electrode on the back side of the battery piece B coincide with each other, and adopts materials such as conductive adhesive, solder strip or tin paste to form physical connection and conductive connection between the two electrodes.

The preparation process of the laminated tile assembly in the prior art has two kinds, for example, as provided in chinese patent CN108091705B, the method one: laser pre-cutting the whole piece → printing the whole piece of conductive adhesive → breaking the piece into small pieces → stacking the pieces into strings; the second method comprises the following steps: printing the whole conductive adhesive → pre-cutting the whole laser → breaking the piece into small pieces → stringing the laminated pieces.

The heterojunction battery is applied to the manufacture of high-efficiency components due to the advantages of few manufacturing procedures, high efficiency, no LID, no PID, no low temperature coefficient and the like, and the process of the existing heterojunction battery brings the following problems:

(1) the high temperature of laser cutting can cause damage of amorphous silicon and TCO films and damage layers can be generated on cutting surfaces to cause serious edge recombination, so that the efficiency of the cell is reduced, the cell is generally cut into 5-7 pieces by 4-6 laser in the cutting process of the stack tile assembly cell, the cutting efficiency loss and the number of cutting tracks form positive correlation relationship, and the stack tile assembly has limitation in matching application with heterojunction cells.

(2) In consideration of the PN junction characteristics, cutting loss and process yield of the battery piece, the laser cutting splitting process usually adopts 40-60% of depth of the battery piece to be cut, and then mechanical splitting is performed, but the battery piece can generate fine defects on a cutting surface after being cut, the larger the uncut depth proportion in the splitting process is, the larger the stress generated by breaking the piece is, the more easily the splitting failure is generated, and the larger the number of cutting channels is, the higher the failure rate is.

(3) The existing process flow is to print the whole piece and then split the piece, conductive adhesive on the battery strip with poor split piece is wasted, and the poor split piece procedure is increased and the conductive adhesive waste is increased due to the fact that the heterojunction battery silicon wafer is thinner.

(4) The power of the assembly is increased by adopting large-size battery pieces such as 182 and 210 batteries, the reduction of the power cost is the main direction for lowering the cost and increasing the product competitiveness in the industry at present, the heterojunction battery piece is usually made of a thinner silicon wafer with the thickness of 140mm-160mm, the warpage of the silicon wafer is increased along with the increase of the size of the silicon wafer, and the problem of uneven coating on the battery is caused by the overlarge warpage of the silicon wafer, so that the battery efficiency is influenced.

(5) The conductive adhesive is usually 60% -80% of silver powder for conducting electricity, the resin content playing a bonding role is usually only 20% -40%, and in addition, the heterojunction battery main grid is made of low-temperature silver paste, the welding tension of the heterojunction battery main grid is low, so that a certain risk exists in bonding of the battery piece and the battery piece in the heterojunction laminated tile, the risk possibly causes the problem that the contact resistance of a bonding part of the component in an outdoor high-low temperature alternating dynamic environment is increased, the resistance of the contact resistance is increased, the power of the component is attenuated, the safety coefficient of a contact point heating component is reduced, and the like.

Disclosure of Invention

The invention aims to overcome the defects and provides a heterojunction battery plate and a preparation method of a laminated assembly thereof, which can reduce cutting loss in the manufacture of the heterojunction laminated assembly so as to improve the power of the assembly.

The purpose of the invention is realized as follows: a preparation method of a heterojunction battery piece comprises the following steps:

laser cutting: selecting a substrate silicon wafer, cutting the substrate silicon wafer into two or three sub-wafers by laser, and breaking the silicon wafer into small wafers;

cleaning: the small pieces after cutting and splitting are subjected to wool making and cleaning treatment;

depositing an amorphous silicon thin film;

preparing a TCO conductive film;

printing: forming front and back Ag electrodes by screen printing;

and (3) curing: curing to form good ohmic contact between the silver grid line and the TCO conductive film;

testing and grading: a test of the electrical performance of the cells was conducted.

Further, the cutting depth in the laser cutting is 60% or more.

Further, when the TCO conductive film is prepared, because the mask with the width of 0.3mm-0.7mm can be generated around each unit cell due to shielding of the carrier plate, the number of cell units is increased after the silicon wafer is divided into two or three pieces, and the number of masks is increased.

A method for preparing a stack assembly of heterojunction battery plates comprises the following steps:

step one, laser cutting:

cutting and splitting the battery piece according to the design pattern by using laser;

step two, splitting the sheet:

breaking the cut battery pieces into battery pieces according to a precut route;

step three, sorting the small pieces:

sorting the appearance of the battery pieces, selecting out bad pieces, and then loading the pieces;

step four, small conductive adhesive printing and adhesive coating:

conducting conductive adhesive printing is carried out on the sorted qualified battery slices, the printing adopts a sectional printing mode, a conductive bonding material for conducting is coated in a printing or dispensing mode, and then a bonding agent for enhancing the bonding effect is coated;

step five, overlapping the small pieces into a battery string;

welding terminals at two ends of the battery string;

step seven, typesetting and laminating the battery strings,

step eight, an assembly packaging procedure;

and step nine, connecting the junction box.

Furthermore, before cutting in the first step, firstly, screen printing plate design of two divided batteries is performed, two cutting lines are arranged on the two divided batteries according to trisection, three main grid lines are arranged on the front side of each battery, a first main grid line and a second main grid line are respectively arranged on two side edges of each battery, a third main grid line is arranged at a dividing line of the left part of each battery, three main grid lines are arranged on the back side of each battery, a fourth main grid line and a fifth main grid line are arranged at a dividing line of the right part of each battery, the fourth main grid line and the fifth main grid line are arranged on two sides of the dividing line back to back, a sixth main grid line is arranged at a dividing line of the left part of each battery, and the sixth main grid line is arranged at a back-to-back position corresponding to the third main grid line.

Further, before cutting in the first step, firstly, designing a screen printing plate of three-divided cells, wherein the three-divided cells are provided with a cutting line according to two equal parts, two main grid lines are respectively arranged on two side edges of the front surface of each cell, and two main grid lines are arranged back to back at the position of the cutting line on the back surface of each cell.

Furthermore, step four is performed by dispensing or other methods when coating the adhesive because the conductive adhesive is already on the battery piece, and the adhesive is alternately dispensed between the conductive adhesives or between two adjacent conductive adhesives.

Further, in the seventh step, the six battery strings on the left and right of the assembly are connected with the six battery strings on the left through the first bus bar, the second bus bar and the third bus bar are respectively welded with one end of the six battery strings on the left and right, the fourth bus bar is connected with the second bus bar, the fifth bus bar is connected with the third bus bar, and the fourth bus bar and the fifth bus bar are used as the positive and negative output ends of the assembly.

Further, in the ninth step, the junction boxes are separately designed and located at two ends of the assembly.

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the invention, through the improvement of the heterojunction battery manufacturing process and the optimization of the design of the screen printing plate graph of the battery piece, the problem of battery efficiency loss caused by the warping of a silicon wafer in the large-size heterojunction battery manufacturing process is solved, and the power loss of the heterojunction imbricated assembly caused by cutting is reduced, so that the assembly power is improved.

(2) According to the invention, through the improvement of the battery piece and the laminated assembly process flow, the conductive adhesive waste caused by poor splitting and poor splitting in the splitting process is reduced;

the method comprises the steps that a silicon wafer is cut into three or two sub-wafers by laser before the silicon wafer is cleaned, and then the procedures of cleaning, amorphous silicon film deposition, TCO preparation, printing, testing and grading are carried out, wherein the cutting occurs before the amorphous silicon film deposition and the TCO film plating, the cutting depth can adopt more than 60% of cutting depth for cutting, the breaking stress is reduced, the bad fragments caused by laser cutting and splitting are reduced, and the damaged layer caused by cutting can be effectively removed by the cleaning procedure, so the edge composite effect caused by the laser cutting is avoided, the warping of the silicon wafer is reduced after the silicon wafer is cut, and the coating uniformity is also improved;

the assembly end uses laser to cut and split the three-piece or two-piece battery, and the cut battery pieces are three-piece or two-piece batteries, so that the assembly end only needs to be cut once or twice, and the power loss of the assembly caused by cutting is reduced; and after the chips are cracked, the appearance of the chips is sorted, the defective chips are sorted out, and then the chips are printed, so that the waste of the conductive adhesive is avoided.

(3) According to the invention, by adding the coating adhesive, the tension between the sheets is increased, the product reliability risk caused by small bonding tension of the heterojunction low-temperature silver paste and the conductive adhesive is reduced, and the product reliability is improved.

Drawings

Fig. 1 is a process flow diagram of a heterojunction cell of the invention.

FIG. 2 is a schematic diagram of a structure of a cut cell piece with a mask according to the present invention.

Figure 3 is a process flow diagram of a stack assembly of the present invention.

Fig. 4 is a screen layout of a two-piece dicing cell according to embodiment 1 of the present invention.

Fig. 5 is a schematic cutting diagram of embodiment 1 of the present invention.

Fig. 6 is a schematic illustration of the position of print coating of example 1 of the present invention.

Fig. 7 is an enlarged view of the battery cell string of fig. 6.

Fig. 8 is a schematic cell overlap diagram of example 1 of the present invention.

Fig. 9 is a schematic structural view of a battery string according to embodiment 1 of the present invention.

Fig. 10 is a schematic view of welding of an edge bus bar of embodiment 1 of the present invention.

Fig. 11 is a battery string stack diagram according to embodiment 1 of the present invention.

Fig. 12 is a back view of the module of example 1 of the present invention.

Fig. 13 is an electrical schematic diagram of embodiment 1 of the present invention.

Fig. 14 is a screen layout of a three-segment cut cell according to embodiment 2 of the present invention.

Fig. 15 is a schematic position diagram of the printing coating of the battery cell string of example 2 of the present invention.

Wherein:

the liquid crystal display panel comprises a mask 1, a TCO conductive film 2, a first main grid line 3, a second main grid line 4, a third main grid line 5, a fourth main grid line 6, a fifth main grid line 7, a sixth main grid line 8, a first bus bar 9, a second bus bar 10, a third bus bar 11, a fourth bus bar 12 and a fifth bus bar 13.

Detailed Description

Example 1:

referring to fig. 1-2, the invention relates to a method for preparing a heterojunction battery plate, which comprises the following steps:

s1: the laser cutting is carried out, and the laser cutting,

a substrate silicon wafer is selected and cut into two sub-pieces by laser, and the cutting depth is over 60 percent, so that the breaking stress is reduced, and the bad fragments caused by laser cutting and splitting are reduced; breaking the slices into small pieces;

s2: the cleaning is carried out, and the cleaning is carried out,

the small pieces after being cut and broken are subjected to texturing and cleaning treatment, and the cleaning process can effectively remove a damage layer caused by cutting, so that the edge composite effect caused by the laser cutting is avoided, the warping of the silicon wafer is reduced along with the cutting of the silicon wafer, and the coating uniformity is improved;

s3: preparing a double-sided intrinsic amorphous silicon layer by PECVD;

s4: preparing an n-type amorphous silicon doped layer by using plasma enhanced chemical vapor deposition;

s5: preparing a p-type amorphous silicon doped layer by using plasma chemical vapor deposition;

s6: depositing a double-sided TCO conductive film 2 by using an RPD or PVD method; when the TCO conductive film is prepared, because the mask 1 with the width of 0.3mm-0.7mm is generated around each unit cell due to the shielding of the carrier plate, the number of the cell units is increased after the silicon wafer is divided into two pieces, and the number of the mask 1 is also increased, as shown in figure 2;

s7: printing, namely forming front and back Ag electrodes by screen printing;

s8: curing, so that good ohmic contact is formed between the silver grid line and the TCO conductive film 2;

s9: and testing grading to test the electrical property of the battery.

Referring to fig. 3-13, a method of making a heterojunction cell stack assembly according to the present invention comprises the steps of:

s1: the laser cutting is carried out, and the laser cutting,

before cutting, firstly, screen printing plate design of two divided cells is carried out, as a mask 1 is not provided with a TCO conductive film 2 and does not have the current collecting capacity, main grid lines are printed at the mask position through optimization of the screen printing plate main grid design of the cell, then the mask 1 is arranged at two small overlapping positions by utilizing the overlapping characteristic of the manufacturing process of a tile stack assembly, the extra efficiency loss caused by the increase of the mask 1 after the silicon wafer is changed into two units from one unit after the silicon wafer is cut is avoided, grid line positions on the front surface and the back surface of the cell refer to figure 4, the two divided cells are provided with two cutting lines according to trisection, the front surface of the cell is provided with three main grid lines, two sides of the cell are respectively provided with a first main grid line 3 and a second main grid line 4, a division line on the left part of the cell is provided with a third main grid line 5, the back surface of the cell is provided with three main grid lines, and a fourth main grid line 6 and a fifth main grid line 7 are arranged at the division line on the right part of the cell, the fourth main grid line 6 and the fifth main grid line 7 are arranged on two sides of the dividing line back to back, a sixth main grid line 8 is arranged at the dividing line of the left part of the battery piece, and the sixth main grid line 8 is arranged at the back-to-back position corresponding to the third main grid line 5.

The two split batteries are cut and split by laser according to the design pattern, and the cut battery pieces are the two split batteries, so that the assembly end only needs to be cut twice, and the power loss of the assembly caused by cutting is reduced;

s2: the splinter is formed by splitting the wood into pieces,

breaking the cut battery pieces into battery pieces according to a precut route;

s3: the small pieces are sorted out in a small piece sorting way,

sorting the appearance of the battery pieces, selecting out bad pieces, and then loading the pieces;

s4: small pieces of conductive glue are printed and coated with adhesive,

referring to fig. 6 and 7, conducting adhesive printing is performed on the sorted qualified battery pieces, the printing adopts a segmented printing mode, firstly a conducting adhesive material for conducting is coated in a printing or dispensing mode, then an adhesive for enhancing the bonding effect is coated, and dispensing or other modes are required when the adhesive is coated because the conducting adhesive is already on the battery pieces; coating the adhesive between the conductive adhesives at intervals;

s5: the chips are stacked into a battery string,

the adjacent battery chips are overlapped up and down, the overlapping width is 0.1mm-3mm, the conductive adhesive plays a role in bonding interconnection and conduction, the adhesive plays a role in reinforcing bonding strength, and the length of the battery string depends on the number of the chips; see fig. 8 and 9;

s6: the terminals of the battery string are welded,

the edge welding strip with the punching structure is adopted to reduce welding stress, the edge welding strip with the punching structure comprises a single-hole edge welding strip, a double-hole edge welding strip, a long-hole edge welding strip and the like, and the width of the edge welding strip is 5-20 mm; see fig. 10;

s7: the cell strings are laid out and laminated on each other,

the battery pack comprises six battery strings on the left and the right of the assembly, wherein the six battery strings on the left and the six battery strings on the right are in circuit connection through a first bus bar 9, a second bus bar 10 and a third bus bar 11 are respectively welded with one end of each of the six battery strings on the left and the right, a fourth bus bar 12 is connected with the second bus bar 10, a fifth bus bar 13 is connected with the third bus bar 11, and the fourth bus bar 12 and the fifth bus bar 13 are used as positive and negative output ends of the assembly; see fig. 11;

s8: a component packaging process;

s9: the connecting junction boxes are arranged at two ends of the assembly in a split mode, so that the length of the cable is saved, and the connecting junction boxes are shown in figure 12.

Example 2:

referring to fig. 14 to 15, the present invention relates to a method for manufacturing a heterojunction cell, this example 2 is different from example 1,

s1: laser cutting, namely selecting a substrate silicon wafer and cutting the substrate silicon wafer into three sub-wafers by laser;

referring to fig. 14-15, a method of making a heterojunction cell stack assembly according to the invention, this example 2 differs from example 1 in that,

s1: the laser cutting is carried out, and the laser cutting,

referring to fig. 14, before cutting, a screen printing plate design of a three-segment battery is firstly performed, the three-segment battery is provided with a cutting line according to two equal parts, two main grid lines are respectively arranged on two side edges of the front surface of the battery, and two main grid lines are arranged back to back at the position of the cutting line of the back surface of the battery;

the three-piece battery is cut and split by laser according to the design pattern, and the cut battery pieces are three-piece batteries, so that the assembly end only needs to be cut once, and the assembly power loss caused by cutting is reduced;

s4: small pieces of conductive glue are printed and coated with adhesive,

and (15) conducting adhesive printing is carried out on the sorted qualified battery slices, the printing adopts a sectional printing mode, firstly, a conducting adhesive material for conducting is coated in a printing or dispensing mode, then, an adhesive for enhancing the bonding effect is coated, the conducting adhesive is coated on the upper surfaces of the battery slices in a dispensing or other mode, and the adhesive is dispensed between two adjacent conducting adhesives.

The above is only a specific application example of the present invention, and the protection scope of the present invention is not limited in any way. All the technical solutions formed by equivalent transformation or equivalent replacement fall within the protection scope of the present invention.