CN102818979B - Method for measuring photoelectric properties of curved solar batteries - Google Patents

Abstract

The invention aims at providing a method for measuring the photoelectric properties of curved solar batteries. The method comprises the following steps of: measuring the refractive indexes, extinction coefficients, film thicknesses, quantum efficiency and conversion efficiency of planar solar batteries with same film structures; then processing data by virtue of a data analysis and conversion module so as to obtain the corresponding reflectivity, transmittivity, absorptivity and internal quantum efficiency of the curved solar batteries; and finally introducing solar spectrum data under different radiation conditions, so as to obtain the light energy distribution, short-circuit currents and photoelectric conversion efficiency of the curved solar batteries. By utilizing the method provided by the invention, the problem that the light energy distribution and internal quantum efficiency of the curved solar batteries cannot be measured in the prior art is solved, and a powerful technical means is provided for the analysis and design of the curved solar batteries.

Description

A kind of curved solar energy cell photoelectric performance measurement method

Technical field

The invention belongs to technical field of solar batteries, be specifically related to a kind of method of measurement of curved solar energy cell photoelectric performance.

Background technology

Flourish along with photovoltaic industry, develops the novel curved solar energy batteries such as linear, spherical, expands the application of solar cell, becomes gradually the study hotspot in photovoltaic field.The main results of curved solar energy battery comprises: (1) Zou De of Peking University spring teach problem group (Appl.Phys.Lett., 2007,90:073501) on being less than the stainless steel wire of 100um, diameter makes absorbed layer, using wire as to electrode, prepare linear curved solar energy battery.(2) people such as R.A.Gaudiana (Science, 2009,324:232) adopts wire that organic substance applies as main electrode, then is wound around another one metal wire as being prepared by electrode to battery, prepares linear curved solar energy battery.(3) Beijing Zhong Zhihuazheng green energy resource Science and Technology Ltd. combines spherical solar cells with bowl-shape mirror condenser, develops spherical point concentrating solar battery.

Although obtained compared with much progress in curved solar energy battery technology of preparing at present, still had following several respects problem in measuring technique and theoretical research field: (1) existing photometry technology cannot have been measured curved solar energy battery reflectivity, transmissivity and absorptivity; (2) existing quantum efficiency measuring technique cannot be measured curved solar energy battery internal quantum efficiency; (3) due to the curved-surface structure feature of battery, incidence angle and the power density of light to curved surface changes with battery surface graded, there is no at present curved solar energy battery luminous energy distribution statistical method; (4) cannot estimate curved solar energy battery short circuit electric current and conversion efficiency for these reasons.

Summary of the invention

The object of this invention is to provide a kind of curved solar energy cell photoelectric performance measurement method, cannot measure the problems such as the distribution of curved solar energy battery luminous energy and internal quantum efficiency in order to solve prior art.

A photoelectric properties method of measurement for curved solar energy battery, comprises step:

(1) basic parameter of preparation the measurement plane solar energy battery identical with curved solar energy battery structure to be measured;

(2) optical performance parameter of employing equivalent interface method Calculation Plane solar cell;

(3) set up curved solar energy battery measurement model, calculate the optical performance parameter of curved solar energy battery;

(4) internal quantum efficiency of calculating curved solar energy battery;

(5) according to photon density spectrum and curved solar energy battery internal quantum efficiency under curved solar energy battery radiation parameter of living in, obtain curved solar energy battery short circuit electric current;

(6) photoelectric conversion efficiency of estimation curved solar energy battery.

The basic parameter of described measurement plane solar cell comprises refractive index and the extinction coefficient of each tunic, the physical thickness of each tunic, the internal quantum efficiency of described plane solar energy battery, photoelectric conversion efficiency and short circuit current.

Further, in described step (3), setting up curved solar energy battery measurement model refers to taking incident ray as normal and sets up normal plane, on described curved solar energy battery, the projection coordinate of arbitrfary point on normal plane is (x, y), with f (x, what y) represent projection coordinate (x, y) and the origin of coordinates surrounds area, and the optical performance parameter of described curved solar energy battery is:

$P\left(\mathrm{\λ}\right)=\underset{\mathrm{\Δx},\mathrm{\Δy}\→0}{\lim }\underset{\mathrm{\Δx},\mathrm{\Δy}}{\mathrm{\Σ}}[f(x+\mathrm{\Δx},y+\mathrm{\Δy})-f(x,y)]P(x,y,\mathrm{\λ})$

Wherein, the optical performance parameter of the surface points that P (x, y, λ) expression projection coordinate is (x, y) to incident light, λ is incident light wavelength.

Further, described optical performance parameter is reflectivity, transmissivity and absorptivity.

Further, in described step (4), calculate the internal quantum efficiency IQE of curved solar energy battery _c(λ) formula is:

IQE _c(λ)＝IQE(λ)·A _c(λ)

Wherein, IQE (λ) is described plane solar energy battery internal quantum efficiency, A _c(λ) absorptivity of the parallel incident light that the curved solar energy battery recording for step (3) is λ to wavelength.

Further, in described step (5), obtain curved solar energy battery short circuit electric current I _scformula be:

$I_{\mathrm{sc}}={\∫}_{{\mathrm{\λ}}_0}^{{\mathrm{\λ}}_1}{\mathrm{IQE}}_c\left(\mathrm{\λ}\right)\·A_c\left(\mathrm{\λ}\right)\·S\left(\mathrm{\λ}\right)\·1.602\·{10}^{-28}\mathrm{d\λ}$

Wherein S (λ) is the photon density spectrum under described curved solar energy battery radiation parameter of living in.

Further, the formula of the photoelectric conversion efficiency η of described step (6) estimation curved solar energy battery is:

$\mathrm{\η}={\mathrm{\η}}_f\·\frac{I_{\mathrm{sc}}}{I_f}$

Wherein, η _ffor the photoelectric conversion efficiency of described plane solar energy battery, I _ffor the short circuit current of described plane solar energy battery.

Further, curved solar energy battery of the present invention includes but not limited to spherical, hemisphere, ellipse, the various ways such as cylindrical, linear.

The method of measurement of the photoelectric conversion efficiency of curved solar energy battery disclosed by the invention, by preparing and the basic parameter of measuring with the identical plane solar energy battery of curved solar energy battery structure to be measured, then by curved solar energy battery is carried out to modeling, thereby calculate the various optical parametrics of curved solar energy battery, the measuring technique means of existing plane solar energy battery are utilized, just realized the parameter measurement of curved solar energy battery, method is simple, is easy to realize.And modeling and subsequent calculations can be integrated into computer module, be embedded in other instruments and carry out Quick Measurement, have wide range of applications.

Brief description of the drawings

Fig. 1 is curved solar energy battery measuring method flow chart of the present invention;

Fig. 2 is the optical performance parameter schematic diagram of embodiment of the present invention plane battery;

Fig. 3 is embodiment of the present invention curved solar energy battery model schematic diagram;

Fig. 4 is curved solar energy battery of the present invention and corresponding plane battery absorbance curves;

Fig. 5 is the internal quantum efficiency curve of curved solar energy battery of the present invention and corresponding plane battery.

Embodiment

Below in conjunction with drawings and Examples, technical solution of the present invention is described in further details, following examples do not form limitation of the invention.

As shown in Figure 1, below taking cylindrical copper indium gallium selenium solar cell as example, the process step of method of measurement of the present invention comprises the idiographic flow of curved solar energy battery parameter method of measurement of the present invention:

Step 101, preparation and cylindrical copper indium gallium selenium solar cell to be measured have the plane solar energy battery of same film architecture, measure and record its basic parameter.

Particularly, according to the structure of cylindrical copper indium gallium selenium solar cell to be measured, preparation has the plane solar energy battery of same film architecture.Prepared copper-indium-galliun-selenium film solar cell is made up of five layer films, respectively: aluminium-doped zinc oxide (ZnO:Al), high resistant zinc oxide (ZnO), cadmium sulfide (CdS), Copper Indium Gallium Selenide (CuIn _xga _1-xse ₂), molybdenum (Mo), its thickness is respectively: 350nm, 80nm, 60nm, 1500nm, 800nm.

In preparation process, adopt spectroscopic ellipsometers to measure refractive index n and the extinction coefficient k of each tunic, adopt step instrument to measure the physical thickness d of each tunic, and separate stores it.Particularly, refractive index n corresponding each wavelength and extinction coefficient k are left in the document of " Optical_Parameters.txt " by name, film thickness deposit data is in the document of " Parameters_Set.txt " by name.

After the preparation of plane solar energy battery, adopt the internal quantum efficiency IQE (λ) of quantum efficiency tester measurement plane solar cell, adopt transformation efficiency tester test component photoelectric conversion efficiency η _fand short circuit current I _f, and separate stores it.Particularly, internal quantum efficiency IQE (λ) deposit data in the document of by name " Inner_Quantum_Efficiency.txt ", photoelectric conversion efficiency η _ftest result leaves in " Parameters_Set.txt " document.

As direct measurement plane solar cell internal quantum efficiency, can be first with quantum efficiency tester test plane solar energy battery external quantum efficiency EQE (λ), and then with spectrophotometer measurement plane solar energy battery reflectivity R (λ), finally utilize following formula to calculate device internal quantum efficiency:

$\mathrm{IQE}\left(\mathrm{\λ}\right)=\frac{\mathrm{EQE}\left(\mathrm{\λ}\right)}{1-R\left(\mathrm{\λ}\right)}---\left(1\right)$

Simultaneously, photon density under curved solar energy battery to be measured radiation parameter of living in is composed to S (λ) deposit data in " Solar_Radiation.txt " document, photon density spectrum S (λ) tests by spectrum irradiatometer, and standard radiation spectrum is downloaded by country or international standard.

Step 102, employing equivalent interface method are obtained the optical performance parameter (reflectivity, transmissivity and absorptivity) of plane solar energy battery.

Concrete, plane solar energy battery is made up of plural layers, to the reflectivity R (θ of any wavelength X and incidence angle θ, λ), transmissivity T (θ, λ) with absorptivity A (θ, λ) meet multilayer film optical theory, can calculate by equivalent interface method.

From " Parameters_Set.txt " and " Optical_Parameters.txt " document, read the thickness of each tunic and the refractive index under each wavelength and extinction coefficient, then according to equivalent interface method, (equivalent interface method is quoted from 20 pages to 33 pages of " contemporary optics thin film technique " chapter 1, book number: ISBN 978-7-308-04977, publication date: November in 2006 the 1st edition, ) calculate the reflectivity R (θ of plane solar energy battery under arbitrarily wavelength X and incidence angle θ, λ), transmissivity T (θ, λ) with absorptivity A (θ, λ), result is stored in " Flat_Cell_Optics.txt " document, reflectivity R (θ, λ), transmissivity T (θ, λ) with absorptivity A (θ, λ) with the corresponding relation of each wavelength as shown in Figure 2.

Step 103, set up normal plane taking incident ray as normal, set up curved solar energy battery measurement model, calculate the optical performance parameter of curved solar energy battery by the measurement model of curved solar energy battery.

The sensitive surface of curved solar energy battery is bending, therefore surface gradient is everywhere incomplete same, when sunlight is equably when parallel incident, the incidence angle at different gradients place is different with power density, incidence angle difference causes reflectivity, transmissivity and the absorptivity difference at different gradients place, and it is different that power density difference causes the luminous energy at different gradients place to distribute.

Set up normal plane taking incident ray as normal, on curved solar energy battery, the projection coordinate of arbitrfary point on normal plane is (x, y), the absorptivity A of the parallel incident light perpendicular to normal plane that curved surface is λ to wavelength _c(λ) can be expressed as:

$A_c\left(\mathrm{\λ}\right)=\underset{\mathrm{\Δx},\mathrm{\Δy}\→0}{\lim }\underset{\mathrm{\Δx},\mathrm{\Δy}}{\mathrm{\Σ}}[f(x+\mathrm{\Δx},y+\mathrm{\Δy})-f(x,y)]A_c(x,y,\mathrm{\λ})---\left(2\right)$

What wherein, f (x, y) represented projection coordinate (x, y) and the origin of coordinates surrounds area, A _cthe absorptivity of the surface points that (x, y, λ) expression projection coordinate is (x, y) to incident light.

Particularly, as shown in Figure 3, call the area projection function of curved solar energy battery sensitive surface on normal plane, the present embodiment adopts cylindrical, and through the conversion of plane rectangular coordinates and angular coordinate, its area projection function is:

f(x，y)＝f(θ)＝r·l·sinθ (3)

Bring (3) formula into (2), can obtain:

$A_c\left(\mathrm{\λ}\right)=\underset{\mathrm{\Δ\θ}\→0}{\lim }\mathrm{\Σ}[\sin (\mathrm{\θ}+\mathrm{\Δ\θ})-\sin \left(\mathrm{\θ}\right)]A_c(\mathrm{\θ},\mathrm{\λ})\mathrm{\Δ\θ}---\left(4\right)$

It should be noted that the absorptivity A of a certain surface points to incident light _c(θ, λ), equal the A (θ of this point that plane solar energy battery measurement obtains, λ), therefore from Flat_Cell_Optics.txt document, read plane battery absorbance data A (θ, λ), substitution above formula can calculate the absorptivity A of curved solar energy battery to the long incident light of random wave _c(λ).Adopt same procedure can obtain the reflectivity R of curved solar energy battery to parallel incident light _c(λ) with transmissivity T _c(λ), result of calculation leaves in " Curve_Cell_Optics.txt " document, and test result as shown in Figure 4.

Step 104, in conjunction with curved solar energy battery absorptivity A _c(λ), with plane solar cell internal quantum efficiency IQE (λ), calculate curved solar energy battery internal quantum efficiency IQE _c(λ).Computing formula is as follows:

IQE _c(λ)＝IQE(λ)·A _c(λ) (5)

Particularly, read plane battery internal quantum efficiency IQE (λ) data from " Inner_Quantum_Efficiency.txt " document, read curved solar energy battery absorbance data A from " Curve_Cell_Optics.txt " document _c(λ) data, calculate curved solar energy battery internal quantum efficiency IQE by (5) formula _c(λ) data, are stored in " Flat_Cell_Optics.txt " document, and measurement result as shown in Figure 5.

Step 105, according to photon density spectrum S (λ) and curved solar energy battery internal quantum efficiency IQE under curved solar energy battery radiation parameter of living in _c(λ), calculate curved solar energy battery short circuit electric current I _sc, computing formula is as follows:

$I_{\mathrm{sc}}={\∫}_{{\mathrm{\λ}}_0}^{{\mathrm{\λ}}_1}{\mathrm{IQE}}_c\left(\mathrm{\λ}\right)\·A_c\left(\mathrm{\λ}\right)\·S\left(\mathrm{\λ}\right)\·1.602\·{10}^{-28}\mathrm{d\λ}---\left(6\right)$

Wherein, the unit of S (λ) is/(m ²× nm), λ ₀and λ ₁for the scope of sunlight wavelength, generally between value 300nm-1200nm.

Particularly, read solar radiation photon density spectrum data S (λ) from " Solar_Radiation.txt " document, read curved solar energy battery internal quantum efficiency IQE from " Flat_Cell_Optics.txt " document _c(λ) data, calculate the short circuit current I of curved solar energy battery by (6) formula _sc.

Step 106, estimation curved solar energy cell photoelectric conversion efficiency.

The photoelectric conversion efficiency η of solar cell and short circuit current I _sc, open circuit voltage V _oc, relation between fill factor, curve factor FF and cell area S can be expressed as (system of units of all adopting international standards):

$\mathrm{\η}=\frac{I_{\mathrm{sc}}\·V_{\mathrm{oc}}\·\mathrm{FF}}{1000\·S}---\left(7\right)$

Wherein, I _scbe approximated to proportional relationship with irradiation intensity, V _ocbecome logarithmic relationship with irradiation intensity, FF changes little with irradiation intensity.In the situation that irradiation intensity differs not too large, open circuit voltage and fill factor, curve factor can be ignored on the impact of conversion efficiency, and the variation of device conversion efficiency is mainly reflected in the variation of short circuit current.

The photoelectric conversion efficiency that makes plane solar energy battery is η _f, short circuit current is I _f, the photoelectric conversion efficiency η of curved solar energy battery can be expressed as:

$\mathrm{\η}={\mathrm{\η}}_f\·\frac{I_{\mathrm{sc}}}{I_f}---\left(8\right)$

Particularly, read plane battery short circuit current I from " Parameters_Set.txt " document _fand efficiency eta _f, calculate the photoelectric conversion efficiency of curved solar energy battery by (8) formula.

The present embodiment measurement result is as shown in table 1:

	Plane battery	Curved surface battery	Unit	Recruitment
					Reflection photon	3.67E+22	4.37E+22	Photons/m 2	2.42％
Transmission photon	6.56E+14	5.73E+14	Photons/m 2	0
					Absorb photon	2.53E+23	2.46E+23	Photons/m 2	-2.42％
Current density	27.96	27.16	mA/cm 2	-2.86％
					Conversion efficiency	9.36％	9.09％		-2.86％

Can find out from analysis result, the cylindrical surface solar cell of concrete same film architecture reduces by 0.27% than plane battery photoelectric conversion efficiency.Significantly not reducing on the basis of device photoelectric conversion efficiency, convert cylindrical structural to from planar structure, can expand the application of copper indium gallium selenide cell.

It should be noted that, modeling of the present invention and subsequent calculations analytic process can be integrated in a computer system, and internal quantum efficiency IQE (λ), the photoelectric conversion efficiency η of the plane solar energy battery with same film architecture only need be provided _f, short circuit current I _sc, each tunic the parameter such as refractive index n, extinction coefficient k and physical thickness d, can obtain the optical, electrical results of performance analysis of curved solar energy battery.Both the analysis module having can be used as in quantum efficiency tester or IV tester software system uses, and also can be used alone.

Above embodiment is only in order to technical scheme of the present invention to be described but not be limited; in the situation that not deviating from spirit of the present invention and essence thereof; those of ordinary skill in the art can make according to the present invention various corresponding changes or distortion, but these corresponding changes or distortion all should belong to the protection range of the appended claim of the present invention.

Claims (5)

1. a photoelectric properties method of measurement for curved solar energy battery, is characterized in that, comprises step:

(1) prepare the plane solar energy battery identical with curved solar energy battery structure to be measured and measure its basic parameter;

(2) optical performance parameter of Calculation Plane solar cell;

(3) set up curved solar energy battery measurement model, calculate the optical performance parameter of curved solar energy battery;

(4) internal quantum efficiency of calculating curved solar energy battery;

(5) according to photon density spectrum and curved solar energy battery internal quantum efficiency under curved solar energy battery radiation parameter of living in, obtain curved solar energy battery short circuit electric current;

(6) photoelectric conversion efficiency of estimation curved solar energy battery;

In described step (3), setting up curved solar energy battery measurement model refers to taking incident ray as normal and sets up normal plane, on described curved solar energy battery, the projection coordinate of arbitrfary point on normal plane is (x, y), with f (x, y) represent (x of projection coordinate, y) with the origin of coordinates surround area, the optical performance parameter of described curved solar energy battery is:

$P\left(\mathrm{\λ}\right)=\underset{\mathrm{\Δx},\mathrm{\Δy}\→0}{\lim }\underset{\mathrm{\Δx},\mathrm{\Δy}}{\mathrm{\Σ}}[f(x+\mathrm{\Δx},y+\mathrm{\Δy})-f(x,y)]P(x,y,\mathrm{\λ})$

Wherein, the optical performance parameter of the surface points that P (x, y, λ) expression projection coordinate is (x, y) to incident light, λ is incident light wavelength;

The basic parameter of described measurement plane solar cell comprises refractive index and the extinction coefficient of each tunic, the physical thickness of each tunic, the internal quantum efficiency of described plane solar energy battery, photoelectric conversion efficiency and short circuit current;

Described optical performance parameter is reflectivity, transmissivity and absorptivity.

2. the photoelectric properties method of measurement of curved solar energy battery as claimed in claim 1, is characterized in that, according to the basic parameter of described plane solar energy battery, adopts equivalent interface method to obtain the optical performance parameter of plane solar energy battery.

3. the photoelectric properties method of measurement of curved solar energy battery as claimed in claim 1, is characterized in that, calculates the internal quantum efficiency IQE of curved solar energy battery in described step (4) _c(λ) formula is:

IQE _c(λ)＝IQE(λ)·A _c(λ)

Wherein, IQE (λ) is described plane solar energy battery internal quantum efficiency, A _c(λ) absorptivity of the parallel incident light that the curved solar energy battery recording for step (3) is λ to wavelength.

4. the photoelectric properties method of measurement of curved solar energy battery as claimed in claim 3, is characterized in that, obtains curved solar energy battery short circuit electric current I in described step (5) _scformula be:

$I_{\mathrm{sc}}={\∫}_{{\mathrm{\λ}}_0}^{{\mathrm{\λ}}_1}{\mathrm{IQE}}_c\left(\mathrm{\λ}\right)\·A_c\left(\mathrm{\λ}\right)\·S\left(\mathrm{\λ}\right)\·1.602\·{10}^{-28}\mathrm{d\λ}$

Wherein S (λ) is the photon density spectrum under described curved solar energy battery radiation parameter of living in, λ ₀and λ ₁for the scope of sunlight wavelength.

5. the photoelectric properties method of measurement of curved solar energy battery as claimed in claim 4, is characterized in that, the formula of the photoelectric conversion efficiency η of described step (6) estimation curved solar energy battery is:

$\mathrm{\η}={\mathrm{\η}}_f\·\frac{I_{\mathrm{sc}}}{I_f}$

Wherein, η _ffor the photoelectric conversion efficiency of described plane solar energy battery, I _ffor the short circuit current of described plane solar energy battery.