阅读说明：本技术 Hbc高效太阳能电池背电极连接及封装一体化结构 (HBC high-efficiency solar cell back electrode connection and packaging integrated structure ) 是由 许志 于 2019-03-18 设计创作，主要内容包括：本发明公开了HBC高效太阳能电池背电极连接及封装一体化结构,从下至上依次铺设透明前板,第一EVA封装材料,无主栅背电极的HBC太阳能电池,电路/封装材料,第二EVA封装材料及背板,HBC太阳能电池背电极引线设有分别连接呈指状交叉分布的P型a-Si：H层和N型a-Si：H层的P型细栅和N型细栅,细栅表面交替分布着主栅和细栅连接时隔离P型细栅和N型细栅的绝缘层,所述HBC太阳能电池背电极分别连接收集P型细栅和N型细栅电流的P型主栅电极和N型主栅电极及各个电池片相互间的串联/并联连接导线直接预制在电路/封装材料上。本发明实现了封装的同时完成了背电极连接和电池片相互间串联/并联连接的一体化操作,延长栅线电极寿命,利于电池组件的电路设计。(The invention discloses a back electrode connecting and packaging integrated structure of an HBC (high-efficiency solar cell), which is characterized in that a transparent front plate, a first EVA (ethylene vinyl acetate copolymer) packaging material, an HBC solar cell without a main grid back electrode, a circuit/packaging material, a second EVA packaging material and a back plate are sequentially laid from bottom to top, and a back electrode lead of the HBC solar cell is provided with P-type a-Si: h layer and N type a-Si: the HBC solar cell comprises a P-type fine grid and an N-type fine grid on an H layer, wherein the surfaces of the P-type fine grid and the N-type fine grid are alternately distributed with insulating layers for isolating the P-type fine grid and the N-type fine grid when the main grid and the fine grid are connected, and the back electrode of the HBC solar cell is respectively connected with a P-type main grid electrode and an N-type main grid electrode for collecting the current of the P-type fine grid and the N-type fine grid and a series/parallel connection lead between each cell slice are directly prefabricated on a circuit/packaging material. The invention realizes the integrated operation of back electrode connection and mutual series/parallel connection of the battery pieces while realizing packaging, prolongs the service life of the grid line electrode and is beneficial to the circuit design of the battery assembly.)

High-efficient solar cell back electrode of HBC connects and encapsulates integrated structure, its characterized in that: transparent front bezel, first EVA packaging material, the HBC solar cell of no main grid back electrode is laid in proper order from supreme down to encapsulation integral structure, directly prefabricated circuit/packaging material that has main grid electrode and each battery piece series connection/parallel connection wire each other at EVA packaging material, second EVA packaging material and backplate, HBC solar cell back electrode lead wire is equipped with and connects the P type a-Si that is finger-like cross distribution respectively: h layer and N type a-Si: the HBC solar cell comprises a P-type fine grid and an N-type fine grid on an H layer, wherein insulating layers for isolating the P-type fine grid and the N-type fine grid when the main grid and the fine grid are connected are alternately distributed on the surfaces of the P-type fine grid and the N-type fine grid, the back electrode of the HBC solar cell is respectively connected with a P-type main grid electrode and an N-type main grid electrode for collecting the current of the P-type fine grid and the N-type fine grid, and series/parallel connecting wires among all cells are directly prefabricated on a circuit/packaging material.

2. The HBC high efficiency solar cell back electrode connection and packaging integrated structure of claim 1, wherein: the P-type fine grid and the N-type fine grid are made of conductive silver paste prepared by a screen printing technology.

3. The HBC high efficiency solar cell back electrode connection and packaging integrated structure of claim 1, wherein: the total number of the P-type fine grids and the N-type fine grids is 200-300, and the line width is 20-60 mu m.

4. The HBC high efficiency solar cell back electrode connection and packaging integrated structure of claim 1, wherein: the insulating layers on the surfaces of the P-type fine grid and the N-type fine grid are distributed in a non-connection area where the main grid and the fine grid are in contact, and the insulating layers are made of insulating ink or insulating glue.

5. The HBC high efficiency solar cell back electrode connection and packaging integrated structure of claim 1, wherein: the length of the insulating layer in the direction parallel to the thin gate is 1-3mm wider than the width of the main gate line, and the width of the insulating layer in the direction perpendicular to the thin gate is 0.2-0.4mm wider than the width of the thin gate line.

6. The HBC high efficiency solar cell back electrode connection and packaging integrated structure of claim 1, wherein: the method for directly prefabricating the P-type main grid electrode, the N-type main grid electrode and the series/parallel connection wires among the battery pieces on the circuit/packaging material comprises the steps of directly bonding the P-type main grid electrode and the N-type main grid electrode or masking the surface of the packaging material and depositing an electrode conductive film.

7. The HBC high efficiency solar cell back electrode connection and packaging integrated structure of claim 1, wherein: the first EVA packaging material, the second EVA packaging material and the circuit/packaging material are at least one of ethylene-vinyl acetate copolymer (EVA), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF) and the like.

8. The HBC high efficiency solar cell back electrode connection and packaging integrated structure of claim 1, wherein: the P-type main grid electrode and the N-type main grid electrode are vertically distributed with the P-type fine grid and the N-type fine grid, and the P-type main grid electrode and the N-type main grid electrode are at least one of copper wires, copper strips, copper films and the like.

9. The HBC high efficiency solar cell back electrode connection and packaging integrated structure of claim 1, wherein: the total number of the P-type main grid electrodes and the N-type main grid electrodes is 20-30, and the P-type main grid electrodes and the N-type main grid electrodes are alternately connected with the P-type fine grids and the N-type fine grids respectively.

10. The HBC high efficiency solar cell back electrode connection and packaging integrated structure of claim 1, wherein: the line width of the P-type main gate electrode and the N-type main gate electrode is 100-500 mu m, and the distance between the adjacent main gate electrodes is 4-8 mm.

Technical Field

The invention relates to the technical field of solar cells, in particular to an HBC high-efficiency solar cell back electrode connection and packaging integrated structure.

Background

In response to global energy resource shortage, climate warming and deterioration of human ecological environment, more and more countries are beginning to implement "sunshine plan" to develop and apply pollution-free renewable solar energy resources. Among them, the development of photovoltaic power generation is the most rapid, and the solar cell is the core of photovoltaic power generation and can directly convert solar energy into electric energy for human use. Silicon-based solar cells, as the first generation cells, are still the highest production and installation worldwide.

At present, the silicon-based solar cell has a plurality of types, and the high-efficiency silicon-based solar cell with the conversion efficiency reaching 25% mainly comprises an emitter PERL, an interdigital back contact IBC, a heterojunction HBC and the like. While heterojunction type back contact (HBC type) crystalline solar cells are a good combination of back contact IBC cells and silicon-based heterojunction HIT cells. Because the front grid lines are not used for shading, the shading loss of the grid lines to sunlight is greatly reduced, and the battery has high short-circuit current; a passivation layer with a good passivation effect is grown on the front surface of the silicon substrate to passivate the surface, and then a SiNx antireflection film is deposited to reduce the reflectivity. Depositing a layer of intrinsic a-Si on the back: h, then depositing N type a-Si in an interdigital distribution: h layer and P-type a-Si: the H layer, due to the high quality hydrogenated amorphous silicon passivation, has a high open circuit voltage. As shown in fig. 1, the electrodes of the HBC battery a are all distributed on the backlight surface, and include a-Si: fine gate electrode a11 of H layer and connecting N-type a-Si: the fine gate electrode A12, the fine gate electrodes A11 and A12 of the H layer are generally screen-printed conductive silver paste and are in a crossed interdigital structure, and then the tail ends of the fine gate electrodes are connected through the main gate electrodes A13 and A14 to realize the collection of the cell current. The main gate electrodes a13 and a14 may be obtained by a silver printing and copper electroplating process, but the main gate electrodes are wide enough because of the large cell current. The silver main grid has the advantages of poor adhesion, large current, large silver paste consumption, high cost and large shading area, and the back side light absorption efficiency is further reduced; the main gate for copper electroplating also has the problems of large copper area, high process precision requirement, environmental pollution, limited development and the like. In addition, only two main grids respectively connect the P-type fine grid electrode and the N-type fine grid electrode, and if the fine grid electrode is broken, the current of the broken part cannot be collected; while the carriers generated far from the main gate electrode need to be collected through the entire fine gate electrode, which results in a higher series resistance of the cell, which will degrade the cell performance. Thus, existing HBC cell back electrode connections still face significant challenges.

At present, back contact batteries in the photovoltaic industry mainly adopt two modes of packaging of a conductive adhesive and a flexible circuit backboard, soldering of a tin-coated copper strip and packaging of a common backboard. The first mode cancels the welding process to reduce the scrap rate caused by welding, but requires special printing and laying equipment, and has higher material price and correspondingly higher assembly production cost. The second mode has low material cost, but cannot avoid fragments caused by welding, and is difficult to adapt to the development needs of future solar cells. In summary, the connection and assembly packaging of the back electrode of the current HBC cell are still mainly done separately in separate process steps.

Disclosure of Invention

In order to solve the problems of back electrode connection and assembly packaging of the conventional high-efficiency HBC solar cell and comprehensively improve the back electrode connection and assembly packaging process of a back contact solar cell, the invention provides an integrated structure for back electrode connection and packaging of the high-efficiency HBC solar cell.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: high-efficient solar cell back electrode of HBC connects and encapsulates integrated structure, encapsulation integrated structure is from supreme transparent front bezel of laying in proper order down, first EVA packaging material, the HBC solar cell of no main grid back electrode, directly prefabricated circuit/packaging material that has main gate electrode and each battery piece series connection/parallel connection wire each other at EVA packaging material, second EVA packaging material and backplate, HBC solar cell back electrode lead wire are equipped with and connect the P type a-Si that is finger-like cross distribution respectively: h layer and N type a-Si: the HBC solar cell comprises a P-type fine grid and an N-type fine grid on an H layer, wherein insulating layers for isolating the P-type fine grid and the N-type fine grid when the main grid and the fine grid are connected are alternately distributed on the surfaces of the P-type fine grid and the N-type fine grid, the back electrode of the HBC solar cell is respectively connected with a P-type main grid electrode and an N-type main grid electrode for collecting the current of the P-type fine grid and the N-type fine grid, and series/parallel connecting wires among all cells are directly prefabricated on a circuit/packaging material.

Furthermore, the P-type fine grid and the N-type fine grid adopt conductive silver paste prepared by a screen printing technology.

Furthermore, the total number of the P-type fine grid and the N-type fine grid is 200-300, and the line width is 20-60 um.

Furthermore, the insulating layers on the surfaces of the P-type fine grid and the N-type fine grid are distributed in a crossed mode in a non-connection area where the main grid and the fine grid are in contact, and the insulating layers are made of insulating ink or insulating glue.

Furthermore, the length of the insulating layer in the direction parallel to the thin gate is 1-3mm wider than the width of the main gate line, and the width of the insulating layer in the direction perpendicular to the thin gate is 0.2-0.4mm wider than the width of the thin gate line.

Furthermore, the method for directly prefabricating the P-type main grid electrode, the N-type main grid electrode and the series/parallel connection wires among the battery pieces on the circuit/packaging material comprises the steps of directly bonding the P-type main grid electrode and the N-type main grid electrode or masking the surface of the packaging material and depositing an electrode conductive film.

Further, the first EVA encapsulant, the second EVA encapsulant and the circuit/encapsulant are at least one of ethylene-vinyl acetate copolymer (EVA), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), and the like.

Furthermore, the P-type main gate electrode and the N-type main gate electrode are vertically distributed with the P-type fine gate and the N-type fine gate, and the P-type main gate electrode and the N-type main gate electrode are at least one of a copper wire, a copper strip, a copper film and the like.

Furthermore, the total number of the P-type main grid electrodes and the N-type main grid electrodes is 20-30, and the P-type main grid electrodes and the N-type main grid electrodes are respectively and alternately connected with the P-type fine grids and the N-type fine grids.

Furthermore, the line width of the P-type main gate electrode and the N-type main gate electrode is 100-500um, and the distance between the adjacent main gate electrodes is 4-8 mm.

From the above description of the structure of the present invention, compared with the prior art, the present invention has the following advantages:

according to the invention, the main grid electrode connected with the back electrode of the HBC battery and the connecting wires connected in series/parallel between the battery pieces during packaging are directly prefabricated on the surface of the packaging material, so that the preparation process of the main grid electrode of the back electrode of the HBC battery and the welding process of series/parallel connection between the battery pieces before packaging of the assembly are reduced, the fragment rate caused by welding is avoided, and the integrated operation of back electrode connection of the HBC high-efficiency solar battery and series/parallel connection between the battery pieces is completed while packaging is realized; the current of the thin grid electrode is collected by replacing two thick main grid lines at the tail end with a plurality of groups of thin main grid lines, so that the problem of high series resistance of the battery caused by the fact that current carriers generated far away from the main grid electrode are collected by the whole thin grid electrode is effectively solved, and the current can be shunted, so that the service life of the grid line electrode is prolonged; the insulating layer on the surface of the fine grid of the back electrode of the HBC battery is arranged, so that the main grid and the fine grid are quickly connected after the assembly is packaged, and connecting wires for series connection and parallel connection among battery pieces are directly prefabricated on the surface of a packaging material, so that the circuit design of the battery assembly is facilitated.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram of the back electrode connection of a conventional HBC high efficiency solar cell;

fig. 2 is a schematic diagram of a back electrode structure of a main gate-free HBC solar cell according to the present invention;

FIG. 3 is a cross-sectional view taken at position a1-a2 of FIG. 2;

FIG. 4 is a cross-sectional view taken at position b1-b2 of FIG. 2;

FIG. 5 is a schematic structural view of an EVA packaging material for prefabricating a main grid electrode of a battery on the surface according to the invention;

FIG. 6 is a schematic view of an HBC solar cell module package structure according to the present invention;

FIG. 7 is a schematic diagram of the back electrode connection structure of the EVA material package of the HBC solar cell without the main grid and the surface prefabricated cell main grid electrode of the invention;

FIG. 8 is a cross-sectional view taken at position a1-a2 of FIG. 7;

FIG. 9 is a cross-sectional view taken at position b1-b2 of FIG. 7.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.