A full back electrode solar cell based on passivation contact technology

Abstract

The present invention discloses a full back electrode solar cell based on passivation contact technology, comprising: a P-type silicon substrate, the back surface of which has a metal contact area and a non-metal contact area; a tunneling oxide layer, arranged on the non-metal contact area on the back surface of the P-type silicon substrate; a local back field, arranged on the metal contact area on the back surface of the P-type silicon substrate; a polycrystalline silicon thin film layer, arranged on the tunneling oxide layer; a eutectic layer, arranged on the local back field; a dielectric film passivation layer, arranged on the polycrystalline silicon thin film layer and the non-metal contact area; a metal positive electrode, arranged on the local back field; and a metal negative electrode, arranged on the polycrystalline silicon thin film layer. The present invention adopts P-type crystalline silicon as a substrate and combines the passivation contact technology to prepare a full back electrode solar cell, which greatly improves the application prospects of P-type crystalline silicon in the full back electrode solar cell technology.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cells, and in particular relates to a full back electrode solar cell based on a passivation contact technology. Background Art

[0002] At present, full back electrode solar cells are highly favored due to their excellent photoelectric conversion efficiency and are one of the mainstream technologies for high-efficiency solar cells. As the name suggests, full back electrode solar cells refer to cells with all metal electrodes on the back of the cell and no electrodes on the front of the cell.

[0003] Since there is no metal grid blocking the front of the full back electrode solar cell, it can greatly increase the short-circuit current of the solar cell, increase the light receiving area, and improve the cell efficiency. At present, the efficiency of the full back electrode solar cell produced by Sunpower in the United States has reached 25%, and the efficiency of the full back electrode solar cell produced by Chinese companies has reached 24.2%.

[0004] At present, all back-electrode solar cells use N-type monocrystalline silicon as the substrate, mainly because N-type monocrystalline silicon has the advantage of long minority carrier lifetime. With the advancement of crystalline silicon preparation technology, the body minority carrier lifetime of P-type monocrystalline silicon has been greatly improved compared with before, reaching more than 1ms, so P-type crystalline silicon also has application prospects in full back-electrode solar cell technology. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a full back electrode solar cell based on passivation contact technology, which uses P-type crystalline silicon as a substrate and combines the passivation contact technology to prepare a full back electrode solar cell.

[0006] The technical solution of the present invention is: a full back electrode solar cell based on passivation contact technology, comprising:

[0007] A P-type silicon substrate, wherein the back surface of the P-type silicon substrate has a metal contact region and a non-metal contact region;

[0008] A tunneling oxide layer is disposed on a non-metallic contact region on the back surface of the P-type silicon substrate;

[0009] A local back field is provided on a metal contact region on the back surface of the P-type silicon substrate;

[0010] A polysilicon thin film layer is disposed on the tunnel oxide layer;

[0011] The eutectic layer is disposed on the local back surface field;

[0012] A dielectric film passivation layer, disposed on the polysilicon thin film layer and the non-metallic contact area;

[0013] A metal positive electrode is arranged on the local back surface field;

[0014] The metal negative electrode is arranged on the polysilicon thin film layer.

[0015] Preferably, the tunneling oxide layer is disposed on the non-metallic contact region on the back surface of the P-type silicon substrate by thermal oxidation or wet chemical oxidation.

[0016] Preferably, the tunneling oxide layer is a silicon dioxide film.

[0017] Preferably, the silicon dioxide film has a thickness of 0.1 to 10 nm.

[0018] Preferably, the polysilicon thin film layer is deposited on the tunnel oxide layer by low pressure chemical vapor deposition or plasma chemical vapor deposition, and the thickness of the polysilicon thin film layer is 1 to 1000 nm.

[0019] Preferably, the P-type silicon substrate is P-type single crystal silicon or P-type polycrystalline silicon.

[0020] Preferably, the local back field is a local aluminum back field or a local boron back field.

[0021] Preferably, it further comprises a front surface structure arranged on the front surface of the P-type silicon substrate, wherein the front surface structure comprises:

[0022] A front surface anti-reflection suede structure is arranged on the front surface of the P-type silicon substrate;

[0023] A front surface field, arranged on the front surface anti-reflection suede layer;

[0024] The front surface anti-reflection film is arranged on the front surface field.

[0025] Preferably, the front surface anti-reflection velvet structure is a pyramid velvet structure or a corrosion pit velvet structure.

[0026] Preferably, the front surface anti-reflection film is a silicon nitride film.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] The present invention adopts P-type crystalline silicon as a substrate and combines passivation contact technology to prepare a full back electrode solar cell, which greatly improves the application prospect of P-type crystalline silicon in full back electrode solar cell technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the present invention. DETAILED DESCRIPTION

[0030] Example 1

[0031] like Figure 1 As shown, a full back electrode solar cell based on passivation contact technology includes:

[0032] A P-type silicon substrate 1, wherein the back surface of the P-type silicon substrate 1 has a metal contact area and a non-metal contact area;

[0033] A tunneling oxide layer 2 is provided on a non-metallic contact region on the back surface of the P-type silicon substrate 1;

[0034] A local back field 8 is provided on a metal contact region on the back surface of the P-type silicon substrate 1;

[0035] A polysilicon thin film layer 3 is disposed on the tunnel oxide layer 2;

[0036] A eutectic layer 7 is disposed on the local back surface field 8;

[0037] A dielectric film passivation layer 4, disposed on the polysilicon thin film layer 3 and the non-metallic contact area;

[0038] A metal positive electrode 5 is disposed on the local back surface field 8;

[0039] The metal negative electrode 6 is arranged on the polysilicon thin film layer 3 .

[0040] like Figure 1 As shown, the present invention also includes a front surface structure arranged on the front surface of the P-type silicon substrate, and the front surface structure includes:

[0041] A front surface anti-reflection suede structure is arranged on the front surface of the P-type silicon substrate 1;

[0042] A front surface field, arranged on the front surface anti-reflection suede layer;

[0043] The front surface anti-reflection film is arranged on the front surface field.

[0044] In this embodiment, P-type single crystal silicon is used as a substrate, a pyramid velvet surface is prepared on the front surface of the substrate, a front surface field is formed on the pyramid velvet surface, and silicon nitride SiNx is used as a front surface anti-reflection film; the back surface is polished, a tunneling type SiO2 / poly-Si (silicon dioxide / polycrystalline silicon) film is deposited, and the tunneling type SiO2 / poly-Si film is patterned to form a local aluminum back field area, and then the positive electrode and the negative electrode are screen-printed, and after sintering, a full back electrode solar cell based on passivation contact is formed.

[0045] Example 2

[0046] This embodiment uses P-type polysilicon as the substrate, prepares a etch pit texture surface on the front surface, forms a front surface field on the front surface, and uses silicon nitride SiNx as the front surface anti-reflection film; polishes the back surface, deposits a tunneling SiO2 / poly-Si (silicon dioxide / poly-silicon) film, patterns the tunneling SiO2 / poly-Si film to form a local aluminum back field area, and then screen-prints the positive electrode and the negative electrode, and forms a full back electrode solar cell based on passivation contact after sintering. The rest of the structure of this embodiment is the same as that of embodiment 1.

[0047] Example 3

[0048] This embodiment uses P-type monocrystalline silicon as the substrate, prepares a pyramid velvet surface on the front surface, forms a front surface floating junction on the pyramid velvet surface, and uses SiNx as the front surface anti-reflection film; polishes the back surface, deposits a tunneling SiO2 / poly-Si (silicon dioxide / polycrystalline silicon) film, patterns the tunneling SiO2 / poly-Si film to form a local aluminum back field area, and then screen-prints the positive electrode and the negative electrode, and forms a full back electrode solar cell based on a passivation contact after sintering. The rest of the structure of this embodiment is the same as that of Embodiment 1.

Claims

1. A full back electrode solar cell based on passivation contact technology, characterized in that: include: A P-type silicon substrate, wherein the back surface of the P-type silicon substrate has a metal contact region and a non-metal contact region; A tunneling oxide layer is disposed on a non-metallic contact region on the back surface of the P-type silicon substrate; A local back field is provided on a metal contact region on the back surface of the P-type silicon substrate; A polysilicon thin film layer is disposed on the tunnel oxide layer; The eutectic layer is disposed on the local back surface field; A dielectric film passivation layer, disposed on the polysilicon thin film layer and the non-metallic contact area; A metal positive electrode is arranged on the local back surface field; A metal negative electrode is disposed on the polysilicon thin film layer; It also includes a front surface structure arranged on the front surface of the P-type silicon substrate, and the front surface structure includes: A front surface anti-reflection suede structure is arranged on the front surface of the P-type silicon substrate; A front surface field, arranged on the front surface anti-reflection suede layer; A front surface anti-reflection film, disposed on the front surface field; The tunneling oxide layer is arranged on the non-metal contact area on the back surface of the P-type silicon substrate by thermal oxidation or wet chemical oxidation, and the tunneling oxide layer is a silicon dioxide film.

2. The full back electrode solar cell based on the passivation contact technology according to claim 1, characterized in that: The thickness of the silicon dioxide film is 0.1-10 nm.

3. The full back electrode solar cell based on the passivation contact technology according to claim 1, characterized in that: The polysilicon thin film layer is deposited on the tunnel oxide layer by low pressure chemical vapor deposition or plasma chemical vapor deposition, and the thickness of the polysilicon thin film layer is 1-1000 nm.

4. The full back electrode solar cell based on the passivation contact technology according to claim 1, characterized in that: The P-type silicon substrate is P-type single crystal silicon or P-type polycrystalline silicon.

5. The full back electrode solar cell based on the passivation contact technology according to claim 1, characterized in that: The local back field is a local aluminum back field or a local boron back field.

6. The full back electrode solar cell based on the passivation contact technology according to claim 1, characterized in that: The front surface anti-reflection velvet structure is a pyramid velvet structure or a corrosion pit velvet structure.

7. The full back electrode solar cell based on the passivation contact technology according to claim 1, characterized in that: The front surface anti-reflection film is a silicon nitride film.

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