Back contact battery and its components, and electrostatic spinning coating device

Abstract

The present invention discloses a back-contact battery and its components, and an electrostatic spinning coating device, which relate to the technical field of back-contact batteries, comprising: a battery cell body, the battery cell body comprising an N-type single-crystal silicon wafer, a first surface, and a second surface: the first surface is staggered with a first polarity region and a second polarity region, which are separated from each other by an isolation region; the first polarity region is composed of a tunneling oxide layer, a first doped silicon carbide layer, and a fluorine-doped tin oxide layer from the inside to the outside; the second polarity region is composed of a tunneling oxide layer, a second doped silicon carbide layer, and a fluorine-doped tin oxide layer from the inside to the outside; the isolation region is composed of a tunneling oxide layer, an aluminum oxide passivation layer, and a silicon oxynitride anti-reflection layer from the inside to the outside; the present invention prepares a welding strip on a carrier film by electroplating technology, and then transfers and connects it to the first surface of the battery cell, so that the battery cells are connected in series, the diameter of the electroplated welding strip is thinner, the shading area of the first surface of the battery cell is reduced, and the utilization rate of the ground reflected light and the double-sidedness of the back-contact battery component are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of back-contact batteries, and in particular to a back-contact battery and its components, and an electrostatic spinning coating device. Background Art

[0002] Back-contact (BC) cells are a type of crystalline silicon photovoltaic cell technology. Their core feature is that the positive and negative electrodes and metal contacts of the cell are all located on the back of the cell, so that there is no electrode grid line or welding ribbon blocking the front of the cell, maximizing the use of incident light, reducing optical losses, and improving conversion efficiency. There are multiple areas on the back of the back-contact cell, including the positive electrode area, negative electrode area, isolation area, etc., and patterning technology must be used in production.

[0003] At present, back contact (BC) batteries use doped silicon thin films for positive and negative electrodes and inorganic masks such as silicon oxide and silicon nitride, and adopt an etching process to achieve patterning; etching the above silicon thin films and inorganic masks requires the use of highly corrosive solutions such as sodium hydroxide and hydrofluoric acid, or high-energy pulsed lasers, resulting in expensive equipment, high production costs, and low product yields.

[0004] The grid stacking technology is a pan-semiconductor metallization and cell stringing technology designed to reduce silver consumption and shading area, and improve the performance of photovoltaic modules. Its core structure is to prepare a conductive seed layer for collecting current in the welding area of the welding ribbon on the surface of the cell, and then use an extremely fine metal wire welding ribbon to string together to produce the cell module. The conductive seed layer and the metal wire welding ribbon are connected and conductive. The shortcomings of the existing grid stacking technology are: the diameter of the conductive wire welding ribbon is usually greater than 0.1mm. In order to reduce the shading area and improve the conversion efficiency or the double-sidedness of the module, the conductive wire welding ribbon needs to use a triangular thin wire with ultra-high surface reflectivity to improve the utilization rate of light. However, the production of the triangular wire welding ribbon is difficult and the stringing process is more complicated. Summary of the Invention

[0005] The purpose of the present invention is to provide a back contact battery and its components, and an electrospinning coating device to solve the deficiencies in the above-mentioned prior art.

[0006] In order to achieve the above-mentioned object, the present invention provides the following technical solution: a back-contact battery, comprising: a battery cell body, the battery cell body comprising an N-type single crystal silicon wafer, a first surface, and a second surface;

[0007] The first surface is alternately distributed with first polarity regions and second polarity regions, which are separated from each other by isolation regions;

[0008] The first polar region is composed of a tunneling oxide layer, a first doped silicon carbide layer, and a fluorine-doped tin oxide layer from the inside out.

[0009] The second polarity region is composed of a tunneling oxide layer, a second doped silicon carbide layer, and a fluorine-doped tin oxide layer from the inside out.

[0010] The isolation area is composed of a tunnel oxide layer, an aluminum oxide passivation layer, and a silicon oxynitride anti-reflection layer from the inside to the outside.

[0011] The second surface is composed of a phosphorus diffusion front field, a silicon oxide passivation layer, and a silicon oxynitride anti-reflection layer from the inside to the outside.

[0012] Furthermore, the width of the first polarity region and the second polarity region is 0.2 mm to 2 mm, and the width of the isolation region is less than 0.2 mm.

[0013] Furthermore, the tunneling oxide layer is silicon oxide, the first doped silicon carbide layer is p-type boron-doped silicon carbide, the second doped silicon carbide layer is n-type phosphorus-doped silicon carbide, and the sheet resistance of the fluorine-doped tin oxide layer is 5Ω / sq to 200Ω / sq.

[0014] Furthermore, the various thin films on the first surface are prepared by PECVD technology and a lift-off process. The specific preparation method is as follows:

[0015] Step 1: Cleaning and polishing, then preparing the tunnel oxide layer;

[0016] Step 2: Apply a first mask glue on the first polarity region and the isolation region, leaving the second polarity region bare and performing an oxygen plasma cleaning treatment. Then, deposit a second doped silicon carbide layer and an FTO layer. Then, clean and strip the mask glue. The silicon carbide layer and the FTO layer on the mask glue are stripped along with the mask glue. Then, anneal the silicon carbide layer and the FTO layer on the second polarity region.

[0017] Step 3: Coat a second mask glue on the second polarity region and the isolation region, leaving the first polarity region bare and performing an oxygen plasma cleaning treatment. Then, deposit a first doped silicon carbide layer and an FTO layer. Then, clean and strip the mask glue. The silicon carbide layer and the FTO layer on the mask glue are stripped along with the mask glue. Then, anneal the silicon carbide layer and the FTO layer on the first polarity region.

[0018] Step 4: Apply an appropriate amount of the third mask glue on the first polarity region and the second polarity region, expose the edges of each polarity region, perform oxygen plasma cleaning, and then deposit an aluminum oxide passivation layer and a silicon oxynitride anti-reflection layer. After that, clean and strip the mask glue, and the aluminum oxide layer and silicon oxynitride layer on the mask glue are stripped along with the mask glue.

[0019] Furthermore, the PECVD coating temperature and the oxygen plasma cleaning treatment temperature are lower than 200°C, and the annealing temperature is higher than 200°C.

[0020] Furthermore, the first mask glue is composed of carbon, hydrogen, silicon, phosphorus, and oxygen; the second mask glue is composed of carbon, hydrogen, silicon, boron, and oxygen; and the third mask glue is composed of carbon, hydrogen, silicon, nitrogen, and oxygen.

[0021] All three mask adhesives have the properties of thermal cross-linking, adhesive removal temperature higher than 200°C, and easy degradation;

[0022] The mask glue is applied by electrospinning, and the mask glue applied at the wrong position is removed by low-energy picosecond / femtosecond pulse laser ablation.

[0023] An assembly comprising a back-contact cell as described in any one of the preceding items, wherein the cell assembly is produced by string-welding cells together on a carrier film with a solder ribbon attached thereto, the solder ribbon connecting a first polarity region of one cell to a second polarity region of an adjacent cell, wherein an ohmic contact is formed between the solder ribbon and the fluorine-doped tin oxide layer during string welding;

[0024] Furthermore, the soldering strip on the carrier film is prepared by electroplating technology, the core material of the soldering strip is copper, the surface layer is silver or tin, and the diameter of the soldering strip is 0.01 mm to 0.1 mm;

[0025] An ultra-thin metal film and a photoresist layer are sequentially deposited on a carrier film, and a soldering strip is prepared by processes such as exposure, development, and electroplating.

[0026] Furthermore, the carrier film is an organic film, and the electrode needles of the electroplating process penetrate the carrier film and connect with the ultra-thin metal film. The electrode needle heads are buried in the photoresist layer, which increases the number and density of the electrode needles and ensures the uniformity of the diameter of the electroplated solder strip.

[0027] An electrospinning coating device for producing a back contact battery as described in any one of the above items, comprising:

[0028] frame;

[0029] A rotating shaft, which is rotatably connected to the frame;

[0030] Two coating mechanisms, each coating mechanism includes a barrel slidably and rotatably connected to a frame, a sliding rod fixedly connected to the barrel, a stirring rod rotatably connected inside the barrel, and a plurality of stirring blades fixedly connected to the stirring rod;

[0031] The spinning needle is plugged into the mouths of the two barrels;

[0032] Two clamping mechanisms are respectively arranged at the mouth of the barrel in a one-to-one correspondence, and the clamping mechanisms are used to clamp and fix the spinning needle;

[0033] During the rotation of the shaft, there are coating stations and switching strokes in sequence;

[0034] At the coating station: the spinning needle is connected to one of the barrels, and the masking glue in the barrel flows out from the end of the spinning needle. At the same time, the stirring rod in the barrel drives the stirring blades to rotate and stir;

[0035] During the switching stroke: the two stirring rods stop rotating and respectively drive the two barrels to rotate around the axis of the rotating shaft, so that the positions of the two barrels are interchanged. Moreover, during the rotation process, the spinning needle is pulled out from the barrel currently located at the coating station and plugged into the mouth of the other barrel located at the coating station after rotation.

[0036] In the above technical solution, the present invention provides a back contact battery and its components, and an electrospinning coating device:

[0037] 1. The positive and negative passivation layers of the back-contact battery use doped silicon carbide films instead of doped polysilicon films. Carbon and oxygen contamination will increase the resistivity of the doped polysilicon film, but the impact on the doped silicon carbide film is controllable. The present invention uses a doped silicon carbide film passivation layer and utilizes the conductivity of the fluorine-doped tin oxide (FTO) layer to compensate for the insufficient conductivity of the silicon carbide film. Based on this, the present invention adopts a stripping process route and uses an organic mask and a low-energy pulse laser to achieve patterning, thereby solving the problems of expensive equipment, high production costs, and low product yield in the etching process route.

[0038] 2. The soldering ribbon required for the components is produced by electroplating process, and its diameter can be as small as 0.01mm. After greatly reducing the shading area, there is no need to triangulate the soldering ribbon because there will no longer be much gain; no longer requiring the shape of the soldering ribbon, which can reduce the difficulty of soldering ribbon production and the accuracy of string welding; the electroplated soldering ribbon has a thinner diameter, which reduces the shading area of the first surface of the battery cell, improves the utilization rate of the ground reflected light and the double-sidedness of the back contact battery component.

[0039] 3. The spinning coating device drives the stirring blade to rotate by rotating the rotating shaft, so that the masking glue in the barrel will not solidify, and can drive the two barrels to rotate and alternately position at the coating station, so that the coating efficiency is greatly improved; in addition, during the rotation of the two barrels, the spinning needle is passively removed from one barrel and plugged into the other barrel, so that the same spinning needle can be adapted to two barrels at the same time, so that the spinning needle is always in use, ensuring that there is always masking glue flowing in the spinning needle, avoiding the problem of masking glue remaining in the spinning needle solidifying when the spinning needle is not in use, thereby causing the spinning needle to be blocked. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0041] Figure 1 A schematic diagram of serial welding of the first surface of a battery provided by an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of the overall structure of a spinning coating device provided in an embodiment of the present invention;

[0043] Figure 3 A schematic diagram of a cross-sectional structure of a toothed disc provided in an embodiment of the present invention;

[0044] Figure 4 A schematic diagram of the cross-sectional structure of a material barrel provided in an embodiment of the present invention;

[0045] Figure 5 A schematic structural diagram of a clamping mechanism provided in an embodiment of the present invention;

[0046] Figure 6 Schematic diagram of the structure of the fixed plate, rotating plate, and spinning needle provided in an embodiment of the present invention;

[0047] Figure 7 A schematic diagram of the structure of the stirring switching mechanism and the receiving mechanism provided in an embodiment of the present invention;

[0048] Figure 8 A schematic diagram of the sleeve structure provided in an embodiment of the present invention;

[0049] Figure 9 A schematic diagram of a sleeve structure from another angle provided by an embodiment of the present invention;

[0050] Figure 10 A schematic diagram of the structure of the undertaking mechanism provided in an embodiment of the present invention.

[0051] Description of reference numerals:

[0052] 1. Cell body; 11. First polarity region; 12. Second polarity region; 2. Another cell body; 21. First polarity region of another cell body; 22. Second polarity region of another cell body; 3. Isolation region; 4. Welding ribbon; 5. Rotating shaft; 6. Coating mechanism; 61. Material barrel; 62. Sliding rod; 63. Stirring rod; 64. Stirring blade; 7. Spinning needle; 71. Snap-on plate; 72. Connecting plate; 8. Clamping mechanism; 81. Fixed plate; 811. Straight groove; 82. Rotating plate; 821. Arc groove; 83. Clamping rod; 84. Clamping plate; 85. Sliding block; 9. Stirring switching mechanism ;91. Toothed disc;92. Gear;93. Ring;94. First spring;95. Sleeve;951. Ascending section;952. First rotating section;953. Descending section;954. Second rotating section;96. Lifting plate;97. Locking plate;98. Second spring;10. Receiving mechanism;101. Cam;1011. First coaxial section;1012. Inserting section;1013. Second coaxial section;1014. Pulling section;102. Vertical rod;103. Snap-fit frame;104. Third spring;105. Abutting rod;106. Receiving plate;1061. Snap-fit groove;107. Receiving ring. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0054] See also Figure 1-10 A back-contact battery provided by an embodiment of the present invention includes: a battery cell body 1, the battery cell body 1 includes an N-type single crystal silicon wafer, a first surface, and a second surface; wherein the positive and negative electrodes of the battery are arranged on the first surface, and the second surface has no electrode.

[0055] Specifically, the first surface is staggered with first polarity regions 11 and second polarity regions 12, which are separated from each other by isolation regions 3; preferably, the first polarity region 11 is the positive electrode of the battery, the second polarity region 12 is the negative electrode of the battery, and the isolation region 3 is smaller than the polarity region.

[0056] Specifically, the first polarity region 11 is composed of a tunneling oxide layer, a first doped silicon carbide layer, and a fluorine-doped tin oxide FTO layer from the inside out; the second polarity region 12 is composed of a tunneling oxide layer, a second doped silicon carbide layer, and a fluorine-doped tin oxide FTO layer from the inside out.

[0057] The isolation region 3 is composed of a tunneling oxide layer, an aluminum oxide passivation layer, and a silicon oxynitride anti-reflection layer from the inside out.

[0058] The second surface is composed of a phosphorus diffusion front field, a silicon oxide passivation layer, and a silicon oxynitride anti-reflection layer from the inside to the outside.

[0059] Preferably, the phosphorus diffusion front field is a low-doped shallow junction; further preferably, the phosphorus diffusion doping concentration on the surface of the cell is the highest, which is 2 to 10 times the doping concentration of the single crystal silicon wafer.

[0060] Preferably, the width of the first polarity region 11 and the second polarity region 12 is 0.2 mm to 2 mm, and the width of the isolation region 3 is less than 0.2 mm.

[0061] Preferably, the tunneling oxide layer is silicon oxide, the first doped silicon carbide layer is p-type boron-doped silicon carbide, the second doped silicon carbide layer is n-type phosphorus-doped silicon carbide, and the sheet resistance of the fluorine-doped tin oxide FTO layer is 5Ω / sq to 200Ω / sq.

[0062] The various thin films on the first surface are prepared by PECVD technology and a lift-off process. The specific preparation method is as follows:

[0063] Step 1: Cleaning and polishing, then preparing the tunnel oxide layer;

[0064] Step 2: A first masking glue is applied to the first polarity region 11 and the isolation region 3, leaving the second polarity region 12 exposed. An oxygen plasma cleaning process is performed, followed by deposition of a second doped silicon carbide layer and an FTO layer. The masking glue is then cleaned and stripped, and the silicon carbide layer and the FTO layer on the masking glue are stripped along with the masking glue. The silicon carbide layer and the FTO layer on the second polarity region 12 are then annealed.

[0065] Step 3: Coat a second masking glue on the second polarity region 12 and the isolation region 3, leaving the first polarity region 11 bare, perform an oxygen plasma cleaning treatment, then deposit a first doped silicon carbide layer and an FTO layer, then clean and strip the masking glue, and the silicon carbide layer and the FTO layer on the masking glue are stripped along with the masking glue, and then anneal the silicon carbide layer and the FTO layer on the first polarity region 11;

[0066] Step 4: Apply an appropriate amount of the third mask glue on the first polarity region 11 and the second polarity region 12, expose the edges of each polarity region, perform oxygen plasma cleaning, and then deposit an aluminum oxide passivation layer and a silicon oxynitride anti-reflection layer. After that, clean and strip the mask glue, and the aluminum oxide layer and silicon oxynitride layer on the mask glue are stripped along with the mask glue.

[0067] The above is the first preparation scheme, and the second preparation scheme is described below.

[0068] The various thin films on the first surface are prepared by PECVD technology and a lift-off process. The specific preparation method is as follows:

[0069] Step 1: Cleaning and polishing, then preparing the tunnel oxide layer;

[0070] Step 2: A third masking paste is applied to the first polarity region 11 and the second polarity region 12, and oxygen plasma cleaning is performed. Then, an aluminum oxide passivation layer and a silicon oxynitride anti-reflection layer are deposited. The masking paste is then cleaned and stripped, and the aluminum oxide layer and the silicon oxynitride layer on the masking paste are stripped along with the masking paste.

[0071] Step 3: Coating a first masking glue on the first polarity region 11 and the isolation region 3, leaving the second polarity region 12 and the edge of the isolation region 3 adjacent to the second polarity region 12 exposed, performing an oxygen plasma cleaning treatment, and then depositing a second doped silicon carbide layer and an FTO layer. The masking glue is then cleaned and stripped, and the silicon carbide layer and the FTO layer on the masking glue are stripped along with the masking glue. Afterwards, the silicon carbide layer and the FTO layer on the second polarity region 12 are annealed.

[0072] Step 4: A second mask glue is applied on the second polarity region 12 and the isolation region 3, and the first polarity region 11 and the edge of the isolation region 3 adjacent to the first polarity region 11 are exposed. Oxygen plasma cleaning is performed, and then a first doped silicon carbide layer and an FTO layer are deposited. The mask glue is then cleaned and stripped off. The silicon carbide layer and the FTO layer on the mask glue are stripped off along with the mask glue, and then the silicon carbide layer and the FTO layer on the first polarity region 11 are annealed.

[0073] The PECVD coating temperature and the oxygen plasma cleaning treatment temperature are lower than 200°C, and the annealing temperature is higher than 200°C.

[0074] The first mask glue is composed of carbon, hydrogen, silicon, phosphorus and oxygen elements; the second mask glue is composed of carbon, hydrogen, silicon, boron and oxygen elements; and the third mask glue is composed of carbon, hydrogen, silicon, nitrogen and oxygen elements.

[0075] All three types of mask glue have the properties of thermal cross-linking, degumming temperature higher than 200℃, and easy degradation.

[0076] Preferably, the mask glue is applied by electrospinning, a mask plate is set between the spinning needle and the battery cell, and pattern holes are engraved on the mask plate. The mask plate is made of a low dielectric constant material, such as silicon dioxide. After the mask glue is applied, the mask glue applied to the wrong position is removed by low-energy picosecond / femtosecond pulse laser ablation.

[0077] A component, comprising a back-contact battery as described in any of the above items, wherein the battery component is produced by string-welding battery cells with a carrier film attached with a welding ribbon 4, the welding ribbon 4 connecting the first polarity region 11 of one battery cell with the second polarity region 12 of an adjacent battery cell, and forming an ohmic contact between the welding ribbon 4 and the fluorine-doped tin oxide FTO layer during string welding.

[0078] The soldering strip 4 on the carrier film is prepared by electroplating technology. The core material of the soldering strip 4 is copper, the surface layer is silver or tin, and the diameter of the soldering strip 4 is 0.01mm to 0.1mm.

[0079] An ultra-thin metal film and a photoresist layer are sequentially deposited on the carrier film, and the soldering strip 4 is prepared by processes such as exposure, development, and electroplating. Specifically, the electrode needles of the electroplating process penetrate the carrier film and connect with the ultra-thin metal film, and the electrode needle heads are buried in the photoresist layer, thereby increasing the number and density of the electrode needles and ensuring the uniformity of the diameter of the electroplated soldering strip 4.

[0080] Specifically, on the first surface of the battery cell body 1, the first polarity region 11 and the second polarity region 12 extend along the first direction and are arranged in parallel; the battery cells in the assembly are arranged alternately along the first direction, the battery cell body 1 and the other battery cell body 2 are arranged alternately, the first polarity region 11 of the battery cell body 1 is aligned with the second polarity region 22 of the other battery cell body 2, and the second polarity region 12 of the battery cell body 1 is aligned with the first polarity region 21 of the other battery cell body 2. The connection rule of the welding ribbon 4 is as follows: Figure 1 shown.

[0081] Electrospinning is a technology for preparing nanofibers. High-voltage static electricity is used to form polymer solutions or melts into thin streams, which are eventually solidified into fiber mats or films on a receiving device, depending on the distance between the spinning needle and the receiving device. The principle of this technology is to subject the polymer solution or melt to high-voltage static electricity of several thousand to tens of thousands of volts, and the charged polymer droplets form jet streams under the action of the electric field force. When the receiving device is far away, the solvent in the stream evaporates or solidifies during the jetting process, and eventually falls on the receiving device to form a fiber mat similar to non-woven fabric. When the receiving device is close, the solvent in the stream has not completely evaporated or solidified, and has already fallen onto the receiving device, and then it will fuse to form a film.

[0082] However, after the coating raw materials in the coating barrel of the existing electrospinning equipment are used up, the raw materials required for coating need to be added to the coating barrel separately, and adding the raw materials requires a certain waiting time. On the one hand, the coating efficiency is greatly reduced. On the other hand, during the waiting time, since some raw materials still remain inside the spinning needle, the raw materials are prone to coagulation during this period, thereby clogging the inside of the needle and preventing the raw materials from flowing out from the end of the spinning needle.

[0083] The electrospinning coating device is used to produce the back contact battery as described above, comprising: a frame; and a rotating shaft 5 rotatably connected to the frame.

[0084] Among them, this embodiment includes a driving source (not shown in the figure) for driving the rotating shaft 5. It can be understood that the driving source only needs to intermittently drive the rotating shaft 5 to rotate, and the rotating shaft 5 drives the gear plate 91, gear 92, stirring rod 63, and stirring blade 64 to rotate, thereby stirring the mask glue in the barrel 61 to prevent the mask glue from solidifying.

[0085] Two coating mechanisms 6, each coating mechanism 6 includes a barrel 61 slidably and rotatably connected to the frame, a slide rod 62 fixedly connected to the barrel 61, a stirring rod 63 rotatably connected in the barrel 61, and a plurality of stirring blades 64 fixedly connected to the stirring rod 63;

[0086] The spinning needle 7 is plugged into the mouth of the two barrels 61;

[0087] Two clamping mechanisms 8 are respectively arranged at the mouth of the barrel 61 in a one-to-one correspondence, and the clamping mechanisms 8 are used to clamp and fix the spinning needle 7;

[0088] During the rotation of the shaft 5, there are coating stations and switching strokes in sequence;

[0089] At the coating station: the spinning needle 7 is connected to one of the barrels 61, and the masking glue in the barrel 61 flows out from the end of the spinning needle 7. At the same time, the stirring rod 63 in the barrel 61 drives the stirring blades 64 to rotate and stir;

[0090] During the switching stroke: the two stirring rods 63 stop rotating, and respectively drive the two barrels 61 to rotate around the axis of the rotating shaft 5, so that the two barrels 61 are interchanged in position, and, during the rotation process, the spinning needle 7 is pulled out from the barrel 61 currently located at the coating station, and plugged into the mouth of the other barrel 61 located at the coating station after rotation.

[0091] In an embodiment of the present invention, specifically, the clamping mechanism 8 includes a fixed plate 81 fixedly connected to the barrel 61, a plurality of straight grooves 811 are provided on the fixed plate 81 in a circular array, and a rotating plate 82 is rotatably connected to the fixed plate 81; specifically, a first torsion spring is provided between the rotating plate 82 and the fixed plate 81; a plurality of arc grooves 821 corresponding to the straight grooves 811 are provided on the rotating plate 82, and a clamping rod 83 is slidably connected between each arc groove 821 and its corresponding straight groove 811, and a clamping plate 84 is fixedly connected to the clamping rod 83, and the clamping plate 84 is abutted against the clamping plate 71.

[0092] The bottom of the clamping plate 84 is provided with an inclined surface. By providing the inclined surface, the rotating plate 82 can be rotated by the abutment of the clamping plate 71, so that the clamping plate 71 can be plugged and connected with the mouth of the barrel 61 and can be smoothly supported and clamped by the top of the clamping plate 84.

[0093] Preferably, in order to enable the clamping rod 83 to slide in a straight line on the rotating plate 82 , a slider 85 is fixedly connected to the top of the clamping rod 83 , and the slider 85 is slidably connected in the straight groove 811 .

[0094] Specifically, a plurality of teeth (not shown in the figure) are fixedly connected to the side wall of the rotating plate 82, and a rack is fixedly connected to the frame, and each tooth is engaged with the rack; wherein, the rack is arc-shaped and is arranged around the axis of the rotating shaft 5; when the slide rod 62 slides in the first rotating section 952, at this time, each tooth is engaged with the rack, thereby driving the rotating plate 82 to rotate through the meshing action therebetween, thereby driving each clamping plate 84 to move away from each other along the radial direction of the rotating plate 82 to cancel the clamping of the spinning needle head 7, and the spinning needle head 7 falls due to the action of gravity, and is received and supported by the receiving mechanism 10.

[0095] Specifically, a clamping plate 71 and a connecting plate 72 are fixedly connected to the spinning needle head 7 .

[0096] In an embodiment of the present invention, a stirring and switching mechanism 9 is also included, which has three functions. The first is to stir the interior of the two barrels 61 to prevent the mask glue from solidifying; the second is to drive the two barrels 61 to switch; the third is that when the clamping mechanism 8 removes the spinning needle 7, it drives the receiving mechanism 10 to receive the falling spinning needle 7, and completes the installation of the barrel 61 and the spinning needle 7 through the autonomous falling of the barrel 61.

[0097] Specifically, the stirring switching mechanism 9 includes a toothed disc 91 fixedly connected to the rotating shaft 5, and gears 92 are fixedly connected to the two stirring rods 63. The two gears 92 are meshed with the toothed disc 91. A collar 93 is rotatably connected to the rotating shaft 5, and a first spring 94 is fixedly connected between the collar 93 and the two sliding rods 62; specifically, the first spring 94 is a compression spring; a sleeve 95 is rotatably connected to the rotating shaft 5, and a travel groove is opened on the sleeve 95; specifically, the travel groove includes an ascending section 951, a first rotating section 952, a descending section 953, and a second rotating section 954 that are interconnected; the two sliding rods 62 are slidably connected in the travel groove, and a lifting plate 96 is vertically slidably connected to the sleeve 95. The lifting plate 96 is in abutment with the top of the two barrels 61, and locking plates 97 are fixedly connected at both ends of the lifting plate 96. The two locking plates 97 are respectively engaged with the two gears 92 in a one-to-one manner; specifically, the end of the locking plate 97 is engaged with the gap between two teeth of the gear 92. Through the engagement, the gear 92 can be restricted from being driven to rotate by the toothed disc 91, so that the rotation of the toothed disc 91 will drive the gear 92 which is relatively stationary to rotate synchronously, that is, drive the two barrels 61 to rotate around the axis of the rotating shaft 5, thereby completing the position exchange of the two barrels 61; a second spring 98 is provided between the lifting plate 96 and the toothed disc 91; the second spring 98 is a compression spring.

[0098] Specifically, if Figure 3 、 Figure 7 As shown, sliding holes are provided at both ends of the lifting plate 96 , and the two sliding holes are slidably connected to the two stirring rods 63 in a one-to-one correspondence.

[0099] In an embodiment of the present invention, a receiving mechanism 10 is also included, which includes a cam 101 fixedly connected to the frame, and two clamping units are provided at the bottom of the ring 93, each clamping unit includes a vertical rod 102 fixedly connected to the ring 93, and the end of the vertical rod 102 is fixedly connected to the clamping frame 103, and a third spring 104 is provided between the clamping frame 103 and the vertical rod 102; the third spring 104 is a tension spring; an abutment rod 105 is fixedly connected to the clamping frame 103, and the abutment rod 105 slides and abuts against the side wall of the cam 101, and a receiving plate 106 is rotatably connected to the frame; specifically, a second torsion spring is provided between the receiving plate 106 and the frame; a clamping groove 1061 is provided on the receiving plate 106, and the clamping groove 1061 is plugged into the end of the clamping frame 103, and a receiving ring 107 is provided on the receiving plate 106.

[0100] Specifically, the cam 101 is provided with a first coaxial section 1011 , an insertion section 1012 , a second coaxial section 1013 , and a withdrawal section 1014 ; wherein the first coaxial section 1011 and the second coaxial section 1013 coincide with the axis of the rotating shaft 5 .

[0101] It can be understood that when the spinning needle head 7 falls, the end of the spinning needle head 7 will pass through the center of the receiving ring 107 and move vertically downward until it falls to the top of the receiving ring 107 and abuts against the connecting plate 72. The spinning needle head 7 is supported by the abutment between the two.

[0102] It can be understood that the electrostatic voltage involved in this embodiment is applied to the coating device according to process requirements. The electrostatic spinning method is an existing technology and will not be described in detail here.

[0103] Working principle: Figure 8 As shown, when the material barrel 61 at the coating station has just started the coating operation, the masking glue in the material barrel 61 is full. Under the action of the gravity of the material barrel 61, the elastic force of the first spring 94 is overcome, so that the slide bar 62 on the material barrel 61 is located at the bottom of the rising section 951. As the coating operation proceeds, the masking glue in the material barrel 61 becomes less and less, so that the slide bar 62 gradually slides vertically upward in the rising section 951. In the process of sliding upward, the lifting plate 96 and the locking plate 97 are driven to rise and fall synchronously through the contact between the material barrel 61 and the lifting plate 96. In the embodiment, the elastic force of the first spring 94 is greater than the elastic force of the second spring 98; until the two locking plates 97 complete the limit engagement of the two gears 92, at this time, the rotation of the toothed disc 91 can no longer drive the expected meshing gear 92 to rotate, but the toothed disc 91 and the gear 92 are relatively stationary. At this time, the rotation of the toothed disc 91 will drive the two gears 92 and the two stirring rods 63 to rotate synchronously, that is, drive the two barrels 61 to rotate around the axis of the rotating shaft 5, and exchange positions, so that the barrel 61 that has completed the coating operation leaves the coating station, and the other barrel 61 to be coated approaches the coating station.

[0104] Following the above, during the process of the two barrels 61 exchanging positions, the movement path of the barrel 61 that leaves the coating station is: the slide rod 62 slides along the first rotating section 952, and when the slide rod 62 is located at the intersection of the first rotating section 952 and the descending section 953, coating glue is added to the barrel 61 to facilitate the next coating operation; after adding the mask glue, the weight of the barrel 61 increases, causing the slide rod 62 to compress the first spring 94 and move vertically downward in the descending section 953.

[0105] Another barrel 61 near the coating station to be coated has the following movement path during rotation: the slide bar 62 slides along the second rotating section 954 to approach the coating station; when the slide bar 62 disengages from the second rotating section 954 and enters the ascending section 951, the mask glue in the barrel 61 is full, and the first spring 94 cannot overcome the gravity of the barrel 61, driving the slide bar 62 to fall to the lowest point of the ascending section 951; as the coating operation progresses, the mask glue in the barrel 61 gradually decreases, causing the slide bar 62 to gradually rise in the ascending section 951.

[0106] Among them, when the two barrels 61 rotate and exchange positions, the clamping mechanism 8 on the barrel 61 that is separated from the coating station will passively release the clamping of the spinning needle 7, causing the spinning needle 7 to fall and be caught by the receiving mechanism 10, and then installed on the other barrel 61. The specific distance is as follows:

[0107] During the rotation of the two barrels 61, since the collar 93 is rotatably connected to the rotating shaft 5 and a first spring 94 is provided between the collar 93 and the two slide bars 62, the rotation of the two barrels 61 will drive the collar 93 to rotate synchronously, and the collar 93 will drive the two vertical bars 102 to rotate synchronously. Figure 7As shown, at this time, the end of one of the clamping frames 103 is plugged into the clamping groove 1061. At this time, the abutment rod 105 slides and abuts against the second coaxial section 1013. Through the plug-in effect between the two, the receiving plate 106 is driven to rotate synchronously; at the same time, during the rotation process, the teeth on the rotating plate 82 are engaged with the rack set on the frame, driving the clamping plates 84 to move away from each other along the radial direction of the rotating plate 82, so as to cancel the clamping of the spinning needle head 7, and the spinning needle The spinning needle head 7 falls due to gravity. After the spinning needle head 7 falls, the receiving ring 107 receives the spinning needle head 7; until the contact rod 105 slides to the position of the pull-out section 1014, the elastic force of the third spring 104 restores the elastic deformation, driving the third spring 104 to contract, driving the relative sliding between the clamping frame 103 and the vertical rod 102, so that the end of the clamping frame 103 is pulled out from the clamping groove 1061. A second torsion spring is provided, and the receiving plate 106 will rotate and reset, and reset to the coating station position synchronously with the spinning needle head 7. According to the principle described above, when the slide bar 62 on the other barrel 61 that rotates toward the coating station slides into the rising section 951, the first spring 94 cannot overcome the gravity of the barrel 61, and the slide bar 62 will move vertically downward along the rising section 951 for a distance. As the barrel 61 descends, the mouth of the barrel 61 approaches the top of the spinning needle head 7, and the clamping plates 84 are abutted against the clamping plates 84 through the clamping plates 71 of the spinning needle head 7, so that the clamping plates 84 move away from each other. In the process of the clamping plates 84 moving away, the rotating plate 82 is driven to rotate passively, causing the first torsion spring to undergo elastic deformation to connect the spinning needle head 7 with the mouth of the barrel 61. After the connection is completed, the first torsion spring restores the elastic force of the elastic deformation, driving the rotating plate 82 to rotate in the opposite direction, so that the clamping plates 84 approach each other, thereby clamping the spinning needle head 7.

[0108] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. A back contact battery, characterized in that: include: The cell body (1) comprises an N-type single crystal silicon wafer, a first surface, and a second surface: The first surface is staggered with first polarity regions (11) and second polarity regions (12), which are separated from each other by an isolation region (3); The width of the first polarity region (11) and the second polarity region (12) is 0.2 mm to 2 mm, and the width of the isolation region (3) is less than 0.2 mm; The first polar region (11) is composed of a tunneling oxide layer, a first doped silicon carbide layer, and a fluorine-doped tin oxide (FTO) layer from the inside to the outside; The second polar region (12) is composed of a tunneling oxide layer, a second doped silicon carbide layer, and a fluorine-doped tin oxide (FTO) layer from the inside to the outside; The tunneling oxide layer is silicon oxide, the first doped silicon carbide layer is p-type boron-doped silicon carbide, the second doped silicon carbide layer is n-type phosphorus-doped silicon carbide, and the sheet resistance of the fluorine-doped tin oxide (FTO) layer is 5Ω / sq to 200Ω / sq; The isolation region (3) is composed of a tunneling oxide layer, an aluminum oxide passivation layer, and a silicon oxynitride anti-reflection layer from the inside to the outside; The second surface is composed of a phosphorus diffusion front field, a silicon oxide passivation layer, and a silicon oxynitride anti-reflection layer from the inside to the outside.

2. A back contact battery according to claim 1, characterized in that: The various thin films on the first surface are prepared by PECVD technology and a lift-off process. The specific preparation method is as follows: Step 1: Cleaning and polishing, then preparing the tunnel oxide layer; Step 2: coating a first mask glue on the first polarity region (11) and the isolation region (3), exposing the second polarity region (12), performing an oxygen plasma cleaning treatment, and then depositing a second doped silicon carbide layer and an FTO layer, and then cleaning and stripping the mask glue, the silicon carbide layer and the FTO layer on the mask glue are stripped along with the mask glue, and then annealing the silicon carbide layer and the FTO layer on the second polarity region (12); Step 3: Coating a second mask glue on the second polarity region (12) and the isolation region (3), leaving the first polarity region (11) bare, performing an oxygen plasma cleaning treatment, and then depositing a first doped silicon carbide layer and an FTO layer, and then cleaning and stripping the mask glue, the silicon carbide layer and the FTO layer on the mask glue are stripped along with the mask glue, and then annealing the silicon carbide layer and the FTO layer on the first polarity region (11); Step 4: Apply an appropriate amount of the third mask glue on the first polarity region (11) and the second polarity region (12), expose the edges of each polarity region, perform oxygen plasma cleaning, and then deposit an aluminum oxide passivation layer and a silicon oxynitride anti-reflection layer. After that, clean and strip the mask glue, and the aluminum oxide layer and silicon oxynitride layer on the mask glue are stripped along with the mask glue.

3. A back contact battery according to claim 2, characterized in that: The PECVD coating temperature and the oxygen plasma cleaning treatment temperature are lower than 200°C, and the annealing temperature is higher than 200°C.

4. A back contact battery according to claim 2, characterized in that: The first mask glue is composed of carbon, hydrogen, silicon, phosphorus, and oxygen elements; the second mask glue is composed of carbon, hydrogen, silicon, boron, and oxygen elements; the third mask glue is composed of carbon, hydrogen, silicon, nitrogen, and oxygen elements; All three mask adhesives are thermally cross-linked, have a debonding temperature higher than 200°C, and are easily degraded. The mask glue is applied by electrospinning, and the mask glue applied at the wrong position is removed by low-energy picosecond / femtosecond pulse laser ablation.

5. A component comprising a back contact cell according to any one of claims 1 to 4, characterized in that: The battery assembly is produced by string-welding battery cells using a carrier film with a welding ribbon (4) attached thereto. The welding ribbon (4) connects a first polarity region (11) of one battery cell with a second polarity region (12) of an adjacent battery cell. During string welding, an ohmic contact is formed between the welding ribbon (4) and a fluorine-doped tin oxide (FTO) layer.

6. An assembly according to claim 5, characterized in that The soldering strip (4) on the carrier film is prepared by electroplating technology, the core material of the soldering strip (4) is copper, the surface layer is silver or tin, and the diameter of the soldering strip (4) is 0.01mm to 0.1mm; An ultra-thin metal film and a photoresist layer are sequentially deposited on a carrier film, and a welding strip (4) is prepared by exposure, development, and electroplating processes.

7. An assembly according to claim 5, characterized in that The carrier film is an organic film, and the electrode needles of the electroplating process penetrate the carrier film and connect with the ultra-thin metal film. The electrode needle heads are buried in the photoresist layer, which increases the number and density of the electrode needles and ensures the uniformity of the diameter of the electroplated welding strip (4).

8. An electrospinning coating device for producing a back contact battery according to any one of claims 1 to 4, characterized in that: include: frame; A rotating shaft (5) is rotatably connected to the frame; Two coating mechanisms (6), each coating mechanism (6) includes a barrel (61) slidably and rotatably connected to a frame, a slide rod (62) fixedly connected to the barrel (61), a stirring rod (63) rotatably connected inside the barrel (61), and a plurality of stirring blades (64) fixedly connected to the stirring rod (63); A spinning needle (7) is plugged into and fitted with the openings of the two barrels (61); Two clamping mechanisms (8) are respectively arranged at the mouth of the barrel (61) in a one-to-one correspondence, and the clamping mechanisms (8) are used to clamp and fix the spinning needle (7); The rotating shaft (5) has a coating station and a switching stroke in sequence during its rotation; At the coating station: the spinning needle (7) is connected and matched with one of the barrels (61), and the mask glue in the barrel (61) flows out from the end of the spinning needle (7). At the same time, the stirring rod (63) in the barrel (61) drives the stirring blades (64) to rotate and stir; During the switching stroke, the two stirring rods (63) stop rotating and respectively drive the two barrels (61) to rotate around the axis of the rotating shaft (5), so that the positions of the two barrels (61) are interchanged. In addition, during the rotation process, the spinning needle (7) is pulled out from the barrel (61) currently located at the coating station and plugged into the mouth of the other barrel (61) located at the coating station after rotation.

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