阅读说明：本技术 一种晶体硅电池及其导电浆料 (Crystalline silicon battery and conductive slurry thereof ) 是由 杨智 魏青竹 倪志春 于 2019-07-31 设计创作，主要内容包括：本发明公开了一种晶体硅电池及其导电浆料,该导电浆料能够匹配晶体硅电池的P型摻杂面的浅结工艺。一种晶体硅电池的导电浆料,按质量百分比计,所述导电浆料包括如下组分：银粉30～90％；有机物载体20～40％；含III族元素的粉末0.5～30％；玻璃粉1～10％。所述含III族元素的粉末为硼粉、镓粉、铟粉、铊粉中的一种或几种的混合物；或,所述含III族元素的粉末为III族元素粉末和铜粉的混合物,所述III族元素粉末为硼粉、镓粉、铟粉、铊粉中的一种或几种的混合物。(The invention discloses a crystalline silicon battery and conductive paste thereof, which can be matched with a shallow junction process of a P-type doping surface of the crystalline silicon battery. The conductive paste for the crystalline silicon battery comprises the following components in percentage by mass: 30-90% of silver powder; 20-40% of an organic carrier; 0.5-30% of powder containing group III elements; 1-10% of glass powder. The powder containing the III group elements is one or a mixture of more of boron powder, gallium powder, indium powder and thallium powder; or the group III element-containing powder is a mixture of group III element powder and copper powder, and the group III element powder is one or a mixture of more of boron powder, gallium powder, indium powder and thallium powder.)

1. The conductive paste for the crystalline silicon battery is characterized by comprising the following components in percentage by mass:

The group III element-containing powder comprises one or more of group III elements except aluminum, and the silver powder, the group III element-containing powder and the glass powder are dispersed in the organic carrier.

2. The conductive paste as claimed in claim 1, wherein the group III element-containing powder is one or a mixture of boron powder, gallium powder, indium powder, and thallium powder.

3. The conductive paste according to claim 1, wherein the group III element-containing powder is a mixture of a group III element powder and copper powder, and the group III element powder is one or more of boron powder, gallium powder, indium powder, and thallium powder.

4. The electroconductive paste according to claim 1, wherein the organic carrier is at least one of carbitol, terpineol, hexyl carbitol, teshenlong, butyl carbitol acetate, dimethyl adipate, or glycol ether.

5. The conductive paste according to claim 1, wherein the conductive paste comprises the following components in percentage by mass:

6. A crystalline silicon battery is characterized by comprising a front metal electrode, a front passivation antireflection layer, a substrate, an oxide thin layer, a polycrystalline silicon layer, a back passivation antireflection layer and a back metal electrode, wherein the front antireflection layer, the substrate, the oxide thin layer, the polycrystalline silicon layer and the back passivation antireflection layer are sequentially stacked, the back metal electrode penetrates through the back passivation antireflection film to form ohmic contact with the polycrystalline silicon layer, the polycrystalline silicon layer is doped with a III group element, and the back metal electrode is made of the conductive paste as claimed in any one of claims 1 to 5.

7. The crystalline silicon cell as claimed in claim 6, wherein the thickness of the polycrystalline silicon layer is 0.02 to 0.2 μm.

8. The crystalline silicon cell as claimed in claim 6, wherein the polysilicon layer is a boron-doped polysilicon layer.

9. the crystalline silicon cell as claimed in claim 6, wherein the substrate has a P-type silicon substrate having a phosphorus doped layer formed on a front surface thereof, the front surface passivation anti-reflection layer is formed on the phosphorus doped layer, and the front surface metal electrode forms an ohmic contact with the phosphorus doped layer through the front surface passivation anti-reflection layer; the oxide thin layer is formed on the back surface of the P-type silicon substrate.

Technical Field

The invention belongs to the field of solar cells, and relates to a crystalline silicon cell and conductive slurry for the crystalline silicon cell.

Background

conventional fossil fuels are increasingly depleted, and of all sustainable energy sources, solar energy is undoubtedly one of the cleanest, most widespread and most potential alternative energy sources. At present, among all solar cells, a silicon solar cell is one of solar cells which are commercially popularized in a wide range, because silicon materials have an extremely abundant reserve in the earth crust, and simultaneously, the silicon solar cell has excellent electrical and mechanical properties compared with other types of solar cells, and the silicon solar cell plays an important role in the photovoltaic field. Therefore, the development of cost-effective silicon solar cells has become a main research direction of photovoltaic enterprises in various countries.

The existing crystalline silicon solar cell mainly uses a single-sided solar cell, namely only the front side of the cell can absorb sunlight and perform photoelectric conversion. Actually, sunlight also reaches the back of the cell through reflection, scattering and the like. However, the back surface of the traditional single-sided crystalline silicon cell is covered by metal aluminum, and sunlight reaching the back surface of the cell cannot penetrate through the silicon substrate, so that the sunlight reaching the back surface of the cell cannot be effectively absorbed. In order to further improve the absorption of solar light by the crystalline silicon cell, the photovoltaic industry is gradually developing a crystalline silicon solar cell which can absorb solar light on both sides, and is generally called a crystalline silicon double-sided solar cell.

Attention is increasingly paid to the crystalline-silicon double-sided battery, and a metallization matching slurry for doping the P-type doping surface (mainly doping with the iii-group element) becomes a new development direction of the crystalline-silicon battery slurry. The metallization pastes applied to the P-type doping surfaces are mainly aluminum paste and silver-aluminum paste.

the existing P-type crystalline silicon double-sided cell mainly comprises the following components: the traditional aluminum layer with the fully covered back surface is optimized to be the aluminum layer with the partially covered back surface, so that sunlight reaching the back surface of the cell can be absorbed by the silicon substrate through the region which is not covered by the aluminum layer to generate photon-generated carriers, and the photoelectric conversion capability of the crystalline silicon solar cell is improved.

However, the back surface of the P-type crystalline silicon cell forms a metallized ohmic contact with a silicon substrate by adopting aluminum, and higher carrier recombination exists in a contact area of aluminum-silicon alloy. The higher carrier recombination limits the further improvement of the photoelectric conversion efficiency of the crystalline silicon solar cell. In order to continuously improve the photoelectric conversion efficiency of the crystalline silicon solar cell, a carrier selective structure can be adopted to reduce the carrier recombination of a metalized region on the back surface of the P-type crystalline silicon double-sided cell.

at present, the preparation of a carrier selective structure on the back of a P-type crystalline silicon cell mainly comprises the following steps: (1) growing a SiOx silicon oxide thin layer on the surface of the crystalline silicon; (2) depositing a Polysilicon polycrystalline silicon layer on the grown SiOx silicon oxide thin layer;

In order to achieve a carrier-selective structure with reduced metal-region recombination, the metallization regions need to be confined within a Polysilicon layer, typically deposited to a thickness of 0.05-0.2 um. Currently, the pastes applied to the P-type doping surface are mainly aluminum paste and silver-aluminum paste, and the aluminum has a relatively strong penetration ability in the silicon material, and in order to match with the silver-aluminum paste, the doping depth of the P-type doping surface is usually more than 0.5um, which is much larger than the thickness of the Polysilicon, so that the expected effect of reducing metal de-recombination cannot be achieved.

Therefore, it is important to develop a conductive paste that can achieve good ohmic contact in the Polysilicon layer with the P-type doping surface by matching the shallow junction process of the P-type doping surface.

Disclosure of Invention

In view of the above technical problems, the present invention is directed to a conductive paste for a crystalline silicon cell, which is capable of matching a shallow junction process of a P-type doping surface of the crystalline silicon cell. The invention also provides a crystalline silicon battery.

in order to achieve the purpose, the invention adopts a technical scheme as follows:

The conductive paste for the crystalline silicon battery comprises the following components in percentage by mass:

The group III element-containing powder comprises one or more of group III elements except aluminum, and the silver powder, the group III element-containing powder and the glass powder are dispersed in the organic carrier.

Here, group III elements are group III elements other than aluminum, including but not limited to: boron, gallium, indium, thallium.

Preferably, the group III element-containing powder is one or a mixture of boron powder, gallium powder, indium powder, and thallium powder.

preferably, the group III element-containing powder is a mixture of group III element powder and copper powder, and the group III element powder is one or a mixture of boron powder, gallium powder, indium powder and thallium powder.

preferably, the organic carrier is at least one of carbitol, terpineol, hexyl carbitol, teshenlong, butyl carbitol acetate, dimethyl adipate, or glycol ether.

preferably, the main component of the glass powder is oxide powder comprising PbO and B₂O₃、SiO₂、BiO₃And one or more of ZnO.

Preferably, the conductive paste comprises the following components in percentage by mass:

the other technical scheme adopted by the invention is as follows:

a crystalline silicon battery comprises a front metal electrode, a front passivation antireflection layer, a substrate, an oxide thin layer, a polycrystalline silicon layer, a back passivation antireflection layer and a back metal electrode, wherein the front antireflection layer, the substrate, the oxide thin layer, the polycrystalline silicon layer and the back passivation antireflection layer are sequentially stacked, the back metal electrode penetrates through the back passivation antireflection film and forms ohmic contact with the polycrystalline silicon layer, a group III element is doped in the polycrystalline silicon layer, and the back metal electrode is made of the conductive slurry.

Preferably, the thickness of the polycrystalline silicon layer is 0.02-0.2 μm.

Preferably, the polysilicon layer is a boron-doped polysilicon layer.

Preferably, the substrate is provided with a P-type silicon substrate, a phosphorus doped layer is formed on the front surface of the P-type silicon substrate, the front surface passivation antireflection layer is formed on the phosphorus doped layer, and the front surface metal electrode penetrates through the front surface passivation antireflection layer to form ohmic contact with the phosphorus doped layer; the oxide thin layer is formed on the back surface of the P-type silicon substrate.

Compared with the prior art, the invention has the following advantages by adopting the scheme:

According to the conductive paste of the crystalline silicon cell, the conductive performance is kept, the penetration depth of substances in the conductive paste in the crystalline silicon is reduced, the shallow P-type doping surface can be matched with the conductive paste in a deep junction manner, and a good ohmic contact effect is achieved.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

fig. 1 is a schematic structural view of a P-type crystalline silicon cell according to an embodiment.

Wherein, 1, a front metal electrode; 2. a SiNx layer; 3. a phosphorus doped layer; 4. a P-type crystalline silicon substrate; 5. a SiOx layer; 6. a Polysilicon layer; 7. an AlOx layer; 8. a SiNx layer; 9. and a back metal electrode.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that the advantages and features of the invention may be more readily understood by those skilled in the art. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The invention provides conductive slurry for a crystalline silicon battery and the crystalline silicon battery. Fig. 1 shows a P-type crystalline silicon cell, which includes a front metal electrode 1, a SiNx layer 2, a phosphorus doped layer 3, a P-type silicon substrate layer 4, a SiOx layer 5, a Polysilicon layer 6, an AlOx layer 7, a SiNx layer 8, and a back metal electrode 9. The phosphorus doped layer 3 is formed on the front surface of a P-type silicon substrate layer 4 of the silicon substrate through doping, the front surface of the silicon substrate is of a pyramid-shaped suede structure, and the back surface of the silicon substrate is a plane. The silicon nitride substrate comprises a SiNx2 layer, a phosphorus doped layer 3, a P-type silicon substrate layer 4, a SiOx layer 5, a Polysilicon polycrystalline silicon layer 6, an AlOx layer 7 and a SiNx layer 8 which are sequentially stacked from top to bottom, a front metal electrode 1 penetrates through the SiNx layer 2 to form ohmic contact with the phosphorus doped layer 3, a back metal electrode 9 penetrates through the SiNx layer 8 and the AlOx layer 7 to form ohmic contact with the Polysilicon polycrystalline silicon layer 6, and the Polysilicon polycrystalline silicon layer 6 is 0.02-0.2 mu m thick and is a boron doped Polysilicon layer. The conductive paste provided by the invention is specifically a conductive paste for a back metal electrode of a crystalline silicon cell.

The conductive paste of the present invention will be described in detail with reference to the following examples.