Method for improving the accuracy of the calculation of the photoelectric conversion efficiency of a solar cell

Abstract

The application discloses a method for improving the calculation accuracy of the photoelectric conversion efficiency of a solar cell, and is characterized in that: the total power loss rate of the solar cell is obtained by analyzing the power loss mechanism of the solar cell, the theoretical photoelectric conversion efficiency of the solar cell is calculated, meanwhile, the related parameters are imported into a solar cell simulation software, the photoelectric conversion efficiency of the solar cell is calculated through the simulation software, the relative error between the theoretical efficiency and the simulation efficiency of the solar cell is calculated by comparison, and the smaller the error is, the higher the calculation accuracy is.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and more specifically to a method for improving the accuracy of calculating the photoelectric conversion efficiency of solar cells. Background Technology

[0002] Photovoltaic conversion efficiency (PDE) is a crucial indicator of a solar cell's performance. With the continuous development of solar cell technology, accurately calculating PEE has become a hot research topic. Traditional PEE calculation methods have inherent errors, especially when considering power loss mechanisms, often failing to fully reflect the actual performance of solar cells. Therefore, developing a method to improve the accuracy of PEE calculation is of great significance.

[0003] The paper "Optimized Design of Solar Cell Grid Lines" by Yang Le and Gao Hua proposed an approximate method for calculating the overall power loss rate of solar cells. This invention compares this method with that proposed method to demonstrate its higher accuracy. The power loss rate η' caused by main grid line shading in that paper... sb Power loss rate η' caused by shading of fine grid lines sf The power loss rate η' caused by the main grid line resistance rb The power loss rate η' caused by the fine grid line resistance rf The power loss rate η' caused by the surface resistance of the solar cell between fine grid lines tl The power loss rate η' caused by the contact resistance between the fine grid lines and the surface of the solar cell cf The specific calculation method is as follows:

[0004]

[0005] Where: A is the length of a single solar cell, B is the width of a single solar cell, S is the spacing between the fine grid lines, and W... b Main gate line width, W f For fine gate line width, J mp and V mp These represent the current density and voltage at the maximum power output point of the solar cell, respectively. rb The bulk resistivity of the main gate line, ρ rf ρ is the bulk resistivity of the fine grid lines. tl ρ is the sheet resistance of the semiconductor layer on the surface of a solar cell. cf t represents the contact resistivity between the fine grid lines and the surface semiconductor of the solar cell. rb α is the thickness of the main gate line, α is the aspect ratio of the fine gate line, and m is 3. Summary of the Invention

[0006] The purpose of this invention is to provide a method for improving the accuracy of calculating the photoelectric conversion efficiency of solar cells. By analyzing the power loss mechanism of solar cells, the overall power loss rate of the solar cells is obtained, and then the theoretical photoelectric conversion efficiency of the solar cells is calculated. Simultaneously, by importing relevant parameters into solar cell simulation software, the photoelectric conversion efficiency of the solar cells is calculated, and the theoretical efficiency and simulated efficiency are compared to calculate the relative error between the two. The smaller the error, the higher the accuracy of the calculation method.

[0007] The technical solution of this invention:

[0008] 1. A method for improving the accuracy of calculating the photoelectric conversion efficiency of a solar cell, characterized in that the length and width of a single cell in the solar cell are represented by A and B, respectively, and the relationship between B and A is B = A / n. b , where n b The number of main grid lines in a solar cell is denoted by S; the spacing between the fine grid lines is denoted by n. f It means that S and n f The relationship can be expressed by a formula. Indicates that the width of the main grid line is W. b The width of the fine grid line is W f .

[0009] 2. A method for improving the accuracy of calculating the photoelectric conversion efficiency of solar cells, characterized in that the calculation method is as follows:

[0010] Step 1: Measure the current density J at the maximum output power point of the solar cell. mp and voltage V mp Measure the volume resistivity ρ of the main grid line of the solar cell rb The volume resistivity ρ of fine grid lines rf The sheet resistance ρ of the surface semiconductor of a solar cell tl The contact resistivity ρ between the fine grid lines and the surface semiconductor of the solar cell cf .

[0011] Step 2: Calculate the current density of the solar cell at its maximum power point under ideal conditions. and voltage

[0012]

[0013]

[0014] Where: η s A is the sum of the shading rates of the main grid lines and the fine grid lines. cell R represents the area of ​​the solar cell. all This is the equivalent resistance of the solar cell.

[0015] Step 3: Calculate the power loss P caused by the main grid line resistance. rb Power loss P caused by fine grid line resistance rf The power loss P caused by the surface resistance of the solar cell between the fine grid lines tl The power loss P caused by the contact resistance between the fine grid lines and the surface of the solar cell cf .

[0016]

[0017] Where: t rb The thickness is the main gate line thickness.

[0018]

[0019] Where: α is the aspect ratio of the fine grid line.

[0020]

[0021] Step 4: Calculate the power loss rate η caused by main bus line shading. sb Power loss rate η caused by shading of fine grid lines sf The power loss rate η caused by the main grid line resistance rb The power loss rate η caused by the fine grid line resistance rf The power loss rate η caused by the surface resistance of the solar cell between fine grid lines tl The power loss rate η caused by the contact resistance between the fine grid lines and the surface of the solar cell cf .

[0022]

[0023] Step 5: Calculate the overall power loss rate η1.

[0024] η1=η sb +η sf +η rb +η rf +η tl +η cf

[0025] Step 6: Calculate the theoretical photoelectric conversion efficiency η2.

[0026]

[0027] Step 7: Import the relevant parameters into the solar energy simulation software to obtain the photoelectric conversion efficiency η3.

[0028] Step 8: Calculate the relative error Δη between the theoretical efficiency and the simulated efficiency of the solar cell.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] This invention provides a more accurate method for calculating the photoelectric conversion efficiency of solar cells through a more rational calculation approach. By analyzing the power loss mechanism of solar cells, the theoretical photoelectric conversion efficiency can be calculated more accurately, and the accuracy of the calculation results can be verified through simulation software, thereby improving the accuracy of photoelectric conversion efficiency calculation. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the solar cell grid structure.

[0032] The attached figures are labeled as follows:

[0033] Figure 1 : 1-Fine grid line, 2-Main grid line. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to specific embodiments.

[0035] In this embodiment, the selected solar cell has a length and width of 125mm*125mm. The length A of the unit solar cell is 125mm, and the width is B. The relationship between B and A is B = A / n. b , where n b The number of main busbars in a solar cell.

[0036] The specific optimization steps are as follows:

[0037] 1. Measure the current density J at the maximum output power point of the solar cell. mp 34mA / cm 2 Voltage V mp The voltage is 0.525V, and the bulk resistivity ρ of the main gate line is... rb 2×10 -6 Ω·cm, volume resistivity ρ of fine grid lines rf 3×10 -6 Ω·cm, the sheet resistance ρ of the surface semiconductor of a solar cell tl The contact resistivity ρ between the fine grid lines and the surface semiconductor of the solar cell is 50Ω / □. cf 2.8×10 -3 Ω·cm 2 .

[0038] 2. Calculate the current density at the maximum power point of the solar cell under ideal conditions using the formula. and voltage

[0039] 3. Calculate power loss: Calculate the power loss P caused by the main grid line resistance according to the formula. rb Power loss P caused by fine grid line resistance rf The power loss P caused by the surface resistance of the solar cell between the fine grid lines tl The power loss P caused by the contact resistance between the fine grid lines and the surface of the solar cell cf .

[0040] 4. Calculate the power loss rate: Calculate the power loss rate η caused by the main busbar shading according to the formula. sb Power loss rate η caused by shading of fine grid lines sf The power loss rate η caused by the main grid line resistance rb The power loss rate η caused by the fine grid line resistance rf The power loss rate η caused by the surface resistance of the solar cell between fine grid lines tl The power loss rate η caused by the contact resistance between the fine grid lines and the surface of the solar cell cf .

[0041] 5. Calculate the overall power loss rate η1 according to the formula.

[0042] 6. The theoretical photoelectric conversion efficiency η2 calculated according to the formula.

[0043] 7. Import the relevant parameters into the solar energy simulation software to obtain the photoelectric conversion efficiency η3.

[0044] 8. Calculate the relative error Δη between the theoretical efficiency and the simulated efficiency of the solar cell according to the formula.

[0045] Figure 1 This is a schematic diagram of the solar cell grid structure. Table 1 compares the approximate calculation method proposed in the paper by Yang Le and Gao Hua and the method proposed in this invention when the number of main grid lines in the solar cell is 2 and 3.

[0046] Table 1. Photoelectric conversion efficiency and accuracy calculated by different methods

[0047]

[0048] Comparing the data and results in the table, it can be seen that when the number of main grid lines in the solar cell is 2 and 3, the approximate calculation methods proposed in Yang Le and Gao Hua's paper "Optimization Design of Solar Cell Grid Lines" have errors of 1.0532% and 1.0538%, respectively. The solar cell photoelectric conversion efficiency calculation method proposed in this invention has errors of only 0.0554% and 0.0555%, respectively, which are far more accurate than the calculation methods in the paper.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for improving the accuracy of calculating the photoelectric conversion efficiency of solar cells, characterized in that... By analyzing the power loss mechanism of solar cells, the overall power loss rate of solar cells is obtained, and the theoretical photoelectric conversion efficiency of solar cells is calculated. At the same time, the relevant parameters are imported into solar cell simulation software, and the photoelectric conversion efficiency of solar cells is calculated through simulation software. The theoretical efficiency and the simulated efficiency of solar cells are compared, and the relative error between the two is calculated. The smaller the error, the higher the accuracy of the calculation method.

2. The method for improving the accuracy of solar cell photoelectric conversion efficiency calculation as described in claim 1, characterized in that, The length and width of the unit cell of the solar cell are represented by A and B, respectively, and the relationship between B and A is B = A / n. b , where n b The number of main grid lines in a solar cell is denoted by S; the spacing between the fine grid lines is denoted by n. f It means that S and n f The relationship can be expressed by a formula. Indicates that the width of the main grid line is W. b The width of the fine grid line is W f .

3. The method for improving the accuracy of solar cell photoelectric conversion efficiency calculation as described in claims 1 and 2, characterized in that, The calculation method is as follows: Step 1: Measure the current density J at the maximum output power point of the solar cell. mp and voltage V mp Measure the volume resistivity ρ of the main grid line of the solar cell rb The volume resistivity ρ of fine grid lines rf The sheet resistance ρ of the surface semiconductor of a solar cell tl The contact resistivity ρ between the fine grid lines and the surface semiconductor of the solar cell cf . Step 2: Calculate the current density of the solar cell at its maximum power point under ideal conditions. and voltage Where: η s A is the sum of the shading rates of the main grid lines and the fine grid lines. cell R represents the area of ​​the solar cell. all This is the equivalent resistance of the solar cell. Step 3: Calculate the power loss P caused by the main grid line resistance. rb Power loss P caused by fine grid line resistance rf The power loss P caused by the surface resistance of the solar cell between the fine grid lines tl The power loss P caused by the contact resistance between the fine grid lines and the surface of the solar cell cf . Where: t rb The thickness is the main gate line thickness. Where: α is the aspect ratio of the fine grid line. Step 4: Calculate the power loss rate η caused by main bus line shading. sb Power loss rate η caused by shading of fine grid lines sf The power loss rate η caused by the main grid line resistance rb The power loss rate η caused by the fine grid line resistance rf The power loss rate η caused by the surface resistance of the solar cell between fine grid lines tl The power loss rate η caused by the contact resistance between the fine grid lines and the surface of the solar cell cf . Step 5: Calculate the overall power loss rate η1. η1=η sb +n sf +n rb +n rf +n tl +n cf Step 6: Calculate the theoretical photoelectric conversion efficiency η2. Step 7: Import the relevant parameters into the solar energy simulation software to obtain the photoelectric conversion efficiency η3. Step 8: Calculate the relative error Δη between the theoretical efficiency and the simulated efficiency of the solar cell. 。

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