Solar cell structure

Abstract

The utility model provides a solar cell structure, which comprises a metal layer, a first ITO layer and a second ITO layer, the first ITO layer and the second ITO layer are arranged on two sides of the metal layer, and the thickness of the first ITO layer is different from that of the second ITO layer. The beneficial effects of the utility model are that the structure has more excellent conductivity and light transmittance than a single-layer ITO film; different positions of the metal layer between the first ITO layer and the second ITO layer are regulated and controlled by controlling the thickness of the first ITO layer and the thickness of the second ITO layer, so that different performance requirements of the solar cell are met.

Description

Technical Field

[0001] The utility model belongs to the technical field of solar cells, in particular to a solar cell structure. Background Art

[0002] HJT solar cells integrate the advantages of crystalline silicon and thin-film solar cells. They have attracted much attention in the industry among high-efficiency crystalline silicon cells due to their high efficiency, simple structure, low energy consumption in the preparation process, low cost, low temperature coefficient, and large double-sided power generation. It has a double-sided symmetrical structure, and the back side can also collect scattered sunlight. The n-type body silicon layer is about 150-200um, with a bandgap of about 1.12eV. The n-type (na-Si:H) and p-type (pa-Si:H) amorphous silicon doping layers are on both sides, with a thickness of about 5-10nm and a bandgap of about 1.7-1.9eV. This produces a difference in band gaps, resulting in discontinuity of the energy band at the interface. Therefore, an intrinsic hydrogenated amorphous silicon thin layer (ia-Si:H) with a thickness of 5-10nm is introduced, which can passivate the dangling bonds between amorphous silicon and crystalline silicon, reduce contact barriers and leakage current, reduce interface state density, and suppress tunneling current, and has a good buffering effect. The photogenerated carriers generated inside the battery are transmitted through the TCO layers on both sides, collected and exported through the gate electrodes printed on its surface, forming a simple structure of a heterojunction battery: front surface gate line / light-incoming side TCO / a-Si:H(n) / a-Si:H(i) / n-type crystalline silicon / a-Si:H(i) / a-Si:H(p) / backlight side TCO / back surface gate line.

[0003] In HJT solar cells, due to the poor conductivity of the amorphous silicon layer (a-Si:H), in order to better collect and transmit carriers, a TCO (Transparent Conductive Oxide) layer is added between the gate and a-Si:H as a connection to compensate for the defect of insufficient lateral transmission capacity of the amorphous silicon layer and form a better ohmic contact with the gate electrode. In addition to the light trapping effect of the velvet structure, it also has an anti-reflection effect as a window layer. In order to obtain more efficient HJT cells, continuously enhancing the conductivity and light transmittance of the TCO layer is the focus of research.

[0004] The existing method for preparing the TCO layer is to deposit an ITO film on the surface of an amorphous silicon layer (a-Si:H) by magnetron sputtering. In order to improve the utilization rate of the target material and the performance of the film layer, a higher power is often used for the deposition of the ITO film. This coating method causes ion bombardment damage to the amorphous silicon layer (a-Si:H), reducing the passivation effect. A single-layer ITO film cannot take into account both light transmittance and conductivity. The existing ITO film is thick and expensive. Utility Model Content

[0005] In view of the above problems, the utility model provides a solar cell structure to solve the above or other problems existing in the prior art.

[0006] To solve the above technical problems, the technical solution adopted by the utility model is: a heterojunction solar cell TCO layer structure, including a metal layer and a first ITO layer and a second ITO layer arranged on both sides of the metal layer, and the thickness of the first ITO layer is different from the thickness of the second ITO layer.

[0007] Furthermore, the thickness of the first ITO layer is greater than the thickness of the second ITO layer.

[0008] Furthermore, the thickness of the first ITO layer is smaller than the thickness of the second ITO layer.

[0009] Furthermore, the metal layer includes, but is not limited to, gold, silver, copper, platinum, palladium or titanium.

[0010] A solar cell structure comprises a cell sheet and the above-mentioned heterojunction solar cell TCO layer structure, wherein the heterojunction solar cell TCO layer structure is arranged on the front and back sides of the cell sheet.

[0011] Furthermore, the cell is a doped amorphous silicon cell or a cell of a microcrystalline silicon layer.

[0012] Furthermore, in the TCO layer structure of the heterojunction solar cell on the front side of the cell, the thickness of the first ITO layer is greater than the thickness of the second ITO layer.

[0013] Furthermore, in the TCO layer structure of the heterojunction solar cell on the back side of the cell, the thickness of the first ITO layer is less than the thickness of the second ITO layer.

[0014] Due to the adoption of the above technical solution, the TCO layer structure of the heterojunction solar cell is the first ITO layer / metal layer / second ITO layer, two ITO layers are provided, and a metal layer is provided between the two ITO layers. This structure has better conductivity than a single-layer ITO film. At the same time, compared with the single-layer ITO film, the thickness of the first ITO layer and the thickness of the second ITO layer are both smaller than the single-layer ITO film, and it has better light transmittance than the single-layer ITO film, while taking both conductivity and light transmittance into consideration; by controlling the thickness of the first ITO layer and the thickness of the second ITO layer, the different positions of the metal layer between the first ITO layer and the second ITO layer are regulated to achieve different performance requirements of the solar cell; this structure is thinner than a single-layer ITO film and has a low preparation cost;

[0015] The first ITO layer is deposited by low-power sputtering, and the second ITO2 layer is deposited by high-power sputtering. Compared with a single-layer ITO, it can effectively reduce the damage to the cell and protect its passivation ability;

[0016] The front side of the battery cell adopts the first structure, that is, the thickness of the first ITO layer is greater than the thickness of the second ITO layer, and the back side of the battery cell adopts the second structure, that is, the thickness of the first ITO layer is less than the thickness of the second ITO layer. This structural design can ensure that the solar cell absorbs enough sunlight and increase conductivity, thereby improving the conversion efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of a structure of a TCO layer structure of a heterojunction solar cell according to an embodiment of the utility model;

[0018] Figure 2 This is a schematic structural diagram of another structure of the TCO layer structure of a heterojunction solar cell according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the structure of depositing a first ITO layer on the front side of a cell according to an embodiment of the utility model;

[0020] Figure 4 It is a schematic diagram of the structure of depositing a first ITO layer on the back side of a cell according to an embodiment of the utility model;

[0021] Figure 5 It is a schematic diagram of the structure of depositing metal layers on the front and back of a battery cell according to an embodiment of the utility model;

[0022] Figure 6 It is a schematic diagram of the structure of depositing a second ITO layer on the front side of a cell according to an embodiment of the utility model;

[0023] Figure 7 It is a schematic diagram of the structure of depositing a second ITO layer on the back of a cell according to an embodiment of the utility model;

[0024] Figure 8 It is a schematic structural diagram of a solar cell according to an embodiment of the utility model.

[0025] In the figure:

[0026] 1. First ITO layer 2. Metal layer 3. Second ITO layer

[0027] 4. Battery Cell DETAILED DESCRIPTION

[0028] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments.

[0029] Figure 1A structural diagram of a heterojunction solar cell TCO layer structure of an embodiment of the utility model is shown. The embodiment relates to a heterojunction solar cell TCO layer structure and a solar cell structure. The heterojunction solar cell TCO layer structure is ITO layer / metal layer / ITO layer. The provision of the metal layer can improve the conductivity of the ITO film and reduce the thickness of the ITO film, thereby improving its light transmittance. The thickness of the ITO layer on both sides of the metal layer is different, and the metal layer is regulated at different positions between the two ITO layers to achieve different performance requirements.

[0030] A TCO layer structure of a heterojunction solar cell, such as Figure 1 and 2 As shown, it includes a metal layer 2 and a first ITO layer 1 and a second ITO layer 3 arranged on both sides of the metal layer 2. The thickness of the first ITO layer 1 is different from the thickness of the second ITO layer 3. The TCO layer structure of the heterojunction solar cell has two structures, one is that the thickness of the first ITO layer 1 is greater than the thickness of the second ITO layer 3, and the other structure is that the thickness of the first ITO layer 1 is less than the thickness of the second ITO layer 3; the TCO layer structure of the heterojunction solar cell is ITO layer / metal layer 2 / ITO layer, and the metal layer 2 is provided to improve the conductivity of the ITO layer film, and at the same time, the thickness of the ITO layer film can be reduced, thereby improving the light transmittance of the ITO layer.

[0031] The thickness of the first ITO layer 1 is different from that of the second ITO layer 3, and different sputtering powers are used for deposition. In some feasible embodiments, the first ITO layer 1 is in contact with the battery cell 4, and the second ITO layer 3 is away from the battery cell 4. The metal layer 2 promotes the growth of the grains of the second ITO layer 3. When the thickness of the second ITO layer 3 is greater than the thickness of the first ITO layer 1, the crystallinity of the second ITO layer 3 is enhanced under the action of the metal layer 2, and the grains of the second ITO layer 3 grow and the size of the grains increases, thereby increasing the conductivity of the TCO layer structure of the heterojunction solar cell and reducing the transmittance; when the thickness of the first ITO layer 1 is greater than the thickness of the second ITO layer 3, the conductivity of the TCO layer structure of the heterojunction solar cell is reduced and the transmittance is increased.

[0032] By setting the thickness of the first ITO layer 1 to be different from that of the second ITO layer 3 , the metal layer 2 can be adjusted at different positions between the thickness of the first ITO layer 1 and the second ITO layer 3 , thereby achieving different performance requirements.

[0033] The setting of the metal layer 2 makes the conductivity of the heterojunction solar cell TCO layer structure better than the conductivity of the heterojunction solar cell TCO layer structure with a single ITO layer. The above-mentioned metal layer 2 includes but is not limited to gold, silver, copper, platinum, palladium or titanium. The material type of the metal layer 2 is selected according to actual needs and no specific requirements are made here.

[0034] Although the metal layer 2 is provided, the thickness of the metal layer 2 is 5-10 nm. Compared with the single-layer ITO layer structure, the thickness of the TCO layer structure of the heterojunction solar cell can be reduced.

[0035] A solar cell structure, such as Figure 8 As shown, it includes a battery cell 4 and the heterojunction solar cell TCO layer structure as described above, and the heterojunction solar cell TCO layer structure is arranged on both sides of the battery cell 4, that is, the heterojunction solar cell TCO layer structure is arranged on the front and back sides of the battery cell 4, wherein, in the heterojunction solar cell TCO layer structure on the front side of the battery cell 4, the thickness of the first ITO layer 1 is greater than the thickness of the second ITO layer 3, and in the heterojunction solar cell TCO layer structure on the back side of the battery cell 4, the thickness of the first ITO layer 1 is less than the thickness of the second ITO layer 3, thereby ensuring that the solar cell can absorb enough sunlight and increase conductivity, thereby improving the conversion efficiency of the solar cell.

[0036] In some feasible embodiments, the first ITO layer 1 is formed by low-power sputtering deposition, and the second ITO layer 3 is formed by high-power sputtering deposition, which can effectively reduce damage to the battery cell 4 and protect the passivation ability of the battery cell 4.

[0037] The above-mentioned cell 4 is a doped amorphous silicon cell or a cell of a microcrystalline silicon layer, which is selected according to actual needs and no specific requirements are made here.

[0038] A method for preparing a solar cell structure comprises the following steps:

[0039] like Figure 3 As shown, a first ITO layer 1 is deposited on the front side of the cell 4, and the cell 4 is introduced into a first sputtering chamber in a PVD device to deposit the first ITO layer 1 on the front side, with a sputtering power of 400-600W;

[0040] like Figure 4 As shown, the first ITO layer 1 is deposited on the back of the cell 4, and the cell 4 with the first ITO layer 1 deposited on the front is introduced into the second sputtering chamber of the PVD equipment to deposit the first ITO layer 1 on the back, and the sputtering power is 400-600W;

[0041] That is, the first ITO layer 1 on the front side of the cell 4 and the first ITO layer 1 on the back side of the cell 4 are both deposited in the sputtering chamber of the PVD equipment, with the same sputtering power, 400-600W.

[0042] The thickness of the first ITO layer 1 on the front side of the battery cell 4 is greater than the thickness of the first ITO layer 1 on the back side of the battery cell 4. The thickness of the first ITO layer 1 on the front side of the battery cell 4 is 20-30nm. The thickness of the first ITO layer 1 on the front side of the battery cell 4 is selected according to actual needs, and no specific requirements are made here. The thickness of the first ITO layer 1 on the back side of the battery cell 4 is 10-20nm. The thickness of the first ITO layer 1 on the back side of the battery cell 4 is selected according to actual needs, and no specific requirements are made here.

[0043] like Figure 5 As shown, a metal layer 2 is deposited on the first ITO layer 1 on the front and back sides of the cell 4, respectively. The cell 4 on which the first ITO layer 1 is deposited on the back side is introduced into the third sputtering chamber of the PVD device to deposit the metal layer 2 on the front and back sides, that is, a metal layer 2 is deposited on the front and back sides of the cell 4, respectively. The thickness of the metal layer 2 is 5-10 nm. The thickness of the metal layer 2 is selected according to actual needs, and no specific requirements are made here.

[0044] like Figure 6 As shown, a second ITO layer 3 is deposited on the front metal layer 2 of the cell 4, and the cell 4 on which the metal layer 2 is deposited is introduced into the fourth sputtering chamber of the PVD equipment to deposit the second ITO layer 3 on the front side, with a sputtering power of 1000-1200W;

[0045] like Figure 7 As shown, a second ITO layer 3 is deposited on the back metal layer 2 of the cell 4, and the cell 4 on which the second ITO layer 3 is deposited on the front is introduced into the fifth sputtering chamber of the PVD equipment to deposit the second ITO layer 3 on the back, with a sputtering power of 1000-1200W;

[0046] That is, the second ITO layer 3 on the front side of the cell 4 and the second ITO layer 3 on the back side of the cell 4 are both deposited in the sputtering chamber of the PVD equipment, with the same sputtering power, ie, 1000-1200W.

[0047] The thickness of the second ITO layer 3 on the front side of the battery cell is less than the thickness of the second ITO layer 3 on the back side of the battery cell 4. The thickness of the second ITO layer 3 on the front side of the battery cell 4 is 10-20nm. The thickness of the second ITO layer 3 on the front side of the battery cell 4 is selected according to actual needs, and no specific requirements are made here. The thickness of the second ITO layer 3 on the back side of the battery cell 4 is 20-30nm. The thickness of the second ITO layer 3 on the back side of the battery cell 4 is selected according to actual needs, and no specific requirements are made here.

[0048] The above-mentioned cell 4 is a doped amorphous silicon cell or a microcrystalline silicon cell.

[0049] The solar cell structure obtained through the above steps is: along the front to back direction of the battery cell 4, it is: the second ITO layer 3, the metal layer 2, the first ITO layer 1, the battery cell 4, the first ITO layer 1, the metal layer 2 and the second ITO layer 3. On the side of the front of the battery cell 4, the thickness of the first ITO layer 1 is greater than the thickness of the second ITO layer 3, and on the side of the back of the battery cell 4, the thickness of the first ITO layer 1 is less than the thickness of the second ITO layer 3.

[0050] The following describes in detail some specific embodiments.

[0051] Embodiment 1

[0052] A method for preparing a solar cell structure comprises the following steps:

[0053] The cell 4 with the doped (p-type or n-type) amorphous silicon or microcrystalline silicon layer is introduced into the first sputtering chamber of the PVD equipment, and the first ITO layer 1 is deposited on the front of the cell 4. The sputtering power is 400W, and the thickness of the first ITO layer 1 is 20nm;

[0054] The cell 4 after the above steps is introduced into the second sputtering chamber of the PVD equipment, and the first ITO layer 1 is deposited on the back of the cell 4. The sputtering power is 400W, and the thickness of the first ITO layer 1 is 10nm.

[0055] The cell 4 after the above steps is introduced into the third sputtering chamber of the PVD equipment to deposit a metal layer 2 on the front and back sides, and the thickness of the metal layer 2 is 5 nm;

[0056] The cell 4 after the above steps is introduced into the fourth sputtering chamber of the PVD equipment, and the second ITO layer 3 is deposited on the front side of the cell 4, the sputtering power is 1000W, and the thickness of the second ITO layer 3 is 10nm;

[0057] The cell 4 after the above steps is introduced into the fifth sputtering chamber of the PVD equipment, and a second ITO layer 3 is deposited on the back of the cell 4. The sputtering power is 1000 W, and the thickness of the second ITO layer 3 is 20 nm.

[0058] The solar cell structure prepared by the above-mentioned method for preparing a solar cell structure is as follows: a heterojunction solar cell TCO layer is arranged on the front and back sides of the cell 4, and the structure of the heterojunction solar cell TCO layer on the front side of the cell 4 is as follows: along the direction from the front side of the cell 4 to the outside, a first ITO layer 1 is arranged on the front side of the cell 4, the thickness of the first ITO layer 1 is 20 nm, a metal layer 2 is arranged on the first ITO layer 1, the thickness of the metal layer 2 is 5 nm, a second ITO layer 3 is arranged on the metal layer 2, and the thickness of the second ITO layer 3 is 10 nm; the structure of the heterojunction solar cell TCO layer on the back side of the cell 4 is as follows: along the direction from the back side of the cell 4 to the outside, a first ITO layer 1 is arranged on the back side of the cell 4, the thickness of the first ITO layer 1 is 10 nm, a metal layer 2 is arranged on the first ITO layer 1, the thickness of the metal layer 2 is 5 nm, a second ITO layer 3 is arranged on the metal layer 2, and the thickness of the second ITO layer 3 is 20 nm.

[0059] Compared with existing solar cells with a single-layer ITO film, the conductivity of this solar cell is increased by 15%, the transmittance is increased by 4%, and the cell conversion efficiency is increased by 0.3%.

[0060] Embodiment 2

[0061] A method for preparing a solar cell structure comprises the following steps:

[0062] The cell 4 with the doped (p-type or n-type) amorphous silicon or microcrystalline silicon layer is introduced into the first sputtering chamber of the PVD device, and the first ITO layer 1 is deposited on the front of the cell 4. The sputtering power is 500W, and the thickness of the first ITO layer 1 is 25nm;

[0063] The cell 4 after the above steps is introduced into the second sputtering chamber of the PVD equipment, and the first ITO layer 1 is deposited on the back of the cell 4. The sputtering power is 500W, and the thickness of the first ITO layer 1 is 15nm.

[0064] The cell 4 after the above steps is introduced into the third sputtering chamber of the PVD equipment to deposit a metal layer 2 on the front and back sides, and the thickness of the metal layer 2 is 8 nm;

[0065] The cell 4 after the above steps is introduced into the fourth sputtering chamber of the PVD equipment, and the second ITO layer 3 is deposited on the front side of the cell 4. The sputtering power is 1100W, and the thickness of the second ITO layer 3 is 15nm.

[0066] The cell 4 after the above steps is introduced into the fifth sputtering chamber of the PVD equipment, and a second ITO layer 3 is deposited on the back of the cell 4. The sputtering power is 1100 W, and the thickness of the second ITO layer 3 is 25 nm.

[0067] The solar cell structure prepared by the above-mentioned method for preparing a solar cell structure is as follows: a heterojunction solar cell TCO layer is arranged on the front and back sides of the cell 4, and the structure of the heterojunction solar cell TCO layer on the front side of the cell 4 is as follows: along the direction from the front side of the cell 4 to the outside, a first ITO layer 1 is arranged on the front side of the cell 4, the thickness of the first ITO layer 1 is 25 nm, a metal layer 2 is arranged on the first ITO layer 1, the thickness of the metal layer 2 is 8 nm, a second ITO layer 3 is arranged on the metal layer 2, and the thickness of the second ITO layer 3 is 15 nm; the structure of the heterojunction solar cell TCO layer on the back side of the cell 4 is as follows: along the direction from the back side of the cell 4 to the outside, a first ITO layer 1 is arranged on the back side of the cell 4, the thickness of the first ITO layer 1 is 15 nm, a metal layer 2 is arranged on the first ITO layer 1, the thickness of the metal layer 2 is 8 nm, a second ITO layer 3 is arranged on the metal layer 2, and the thickness of the second ITO layer 3 is 25 nm.

[0068] Compared with existing solar cells with a single-layer ITO film, the conductivity of the solar cell is increased by 12%, the transmittance is increased by 2%, and the cell conversion efficiency is increased by 0.2%.

[0069] Embodiment 3

[0070] A method for preparing a solar cell structure comprises the following steps:

[0071] The cell 4 with the doped (p-type or n-type) amorphous silicon or microcrystalline silicon layer is introduced into the first sputtering chamber of the PVD device, and the first ITO layer 1 is deposited on the front of the cell 4. The sputtering power is 600W, and the thickness of the first ITO layer 1 is 30nm;

[0072] The cell 4 after the above steps is introduced into the second sputtering chamber of the PVD equipment, and the first ITO layer 1 is deposited on the back of the cell 4. The sputtering power is 600W, and the thickness of the first ITO layer 1 is 20nm.

[0073] The cell 4 after the above steps is introduced into the third sputtering chamber of the PVD equipment to deposit a metal layer 2 on the front and back sides, and the thickness of the metal layer 2 is 10 nm;

[0074] The cell 4 after the above steps is introduced into the fourth sputtering chamber of the PVD equipment, and the second ITO layer 3 is deposited on the front side of the cell 4. The sputtering power is 1200W, and the thickness of the second ITO layer 3 is 20nm.

[0075] The cell 4 after the above steps is introduced into the fifth sputtering chamber of the PVD equipment, and a second ITO layer 3 is deposited on the back of the cell 4. The sputtering power is 1200 W, and the thickness of the second ITO layer 3 is 30 nm.

[0076] The solar cell structure prepared by the above-mentioned method for preparing a solar cell structure is as follows: heterojunction solar cell TCO layers are arranged on the front and back sides of the cell 4, and the structure of the heterojunction solar cell TCO layer on the front side of the cell 4 is as follows: along the direction from the front side of the cell 4 to the outside, a first ITO layer 1 is arranged on the front side of the cell 4, the thickness of the first ITO layer 1 is 30 nm, a metal layer 2 is arranged on the first ITO layer 1, the thickness of the metal layer 2 is 10 nm, a second ITO layer 3 is arranged on the metal layer 2, and the thickness of the second ITO layer 3 is 20 nm; the structure of the heterojunction solar cell TCO layer on the back side of the cell 4 is as follows: along the direction from the back side of the cell 4 to the outside, a first ITO layer 1 is arranged on the back side of the cell 4, the thickness of the first ITO layer 1 is 20 nm, a metal layer 2 is arranged on the first ITO layer 1, the thickness of the metal layer 2 is 10 nm, a second ITO layer 3 is arranged on the metal layer 2, and the thickness of the second ITO layer 3 is 30 nm.

[0077] Compared with existing solar cells with a single-layer ITO film, the conductivity of the solar cell is increased by 10%, the transmittance is increased by 3%, and the cell conversion efficiency is increased by 0.2%.

[0078] Due to the adoption of the above technical solution, the TCO layer structure of the heterojunction solar cell is the first ITO layer / metal layer / second ITO layer, two ITO layers are provided, and a metal layer is provided between the two ITO layers. This structure has better conductivity than a single-layer ITO film. At the same time, compared with the single-layer ITO film, the thickness of the first ITO layer and the thickness of the second ITO layer are both smaller than the single-layer ITO film, and the structure has better light transmittance than the single-layer ITO film, while taking both conductivity and light transmittance into consideration. By controlling the thickness of the first ITO layer and the thickness of the second ITO layer, the metal layer is regulated at different positions between the first ITO layer and the second ITO layer to achieve Different performance requirements for solar cells; this structure is thinner than a single-layer ITO film and has a low preparation cost; the first ITO layer is deposited by low-power sputtering, and the second ITO2 layer is deposited by high-power sputtering, which can effectively reduce damage to the battery cell and protect its passivation ability compared to a single-layer ITO; the front of the battery cell adopts the first structure, that is, the thickness of the first ITO layer is greater than the thickness of the second ITO layer, and the back of the battery cell adopts the second structure, that is, the thickness of the first ITO layer is less than the thickness of the second ITO layer. This structural design can ensure that the solar cell absorbs enough sunlight and increase conductivity, thereby improving the conversion efficiency of the solar cell.

[0079] The above is a detailed description of the embodiments of the utility model, but the contents are only preferred embodiments of the utility model and cannot be considered to limit the scope of implementation of the utility model. All equivalent changes and improvements made within the scope of application of the utility model should still fall within the scope of the patent coverage of the utility model.

Claims

1. A solar cell structure, characterized in that: It includes a battery cell and a heterojunction solar cell TCO layer structure, wherein the heterojunction solar cell TCO layer structure is arranged on the front and back sides of the battery cell, and the heterojunction solar cell TCO layer structure includes a metal layer and a first ITO layer and a second ITO layer arranged on both sides of the metal layer, and the thickness of the first ITO layer is different from the thickness of the second ITO layer.

2. The solar cell structure according to claim 1, characterized in that: The thickness of the first ITO layer is greater than the thickness of the second ITO layer.

3. The solar cell structure according to claim 1, characterized in that: The thickness of the first ITO layer is smaller than the thickness of the second ITO layer.

4. The solar cell structure according to any one of claims 1 to 3, characterized in that: The metal layer includes, but is not limited to, gold, silver, copper, platinum, palladium or titanium.

5. The solar cell structure according to claim 1, characterized in that: The cell is a doped amorphous silicon cell or a cell of a microcrystalline silicon layer.

6. The solar cell structure according to claim 1 or 5, characterized in that: In the heterojunction solar cell TCO layer structure on the front side of the cell, the thickness of the first ITO layer is greater than the thickness of the second ITO layer.

7. The solar cell structure according to claim 6, characterized in that: In the heterojunction solar cell TCO layer structure on the back side of the cell, the thickness of the first ITO layer is less than the thickness of the second ITO layer.

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