A testing method and system for stacked solar cells

Abstract

The present invention discloses a testing method and system for a stacked solar cell, wherein the testing method is as follows: for a stacked solar cell composed of n battery cells, n≥2, the spectral response band of any i-th battery cell is represented by λi, 1≤i≤n, and the testing method comprises the following steps: S1, placing the stacked solar cell to be tested at a testing position, and connecting the positive and negative electrodes to an electronic load; S2, when testing the i-th battery cell, adjusting the light intensity corresponding to the λi band to zero, and adjusting the light intensity of the corresponding bands of other battery cells to no less than two standard sunlight, and then reading the current value I through the electronic load. i1 ; S3, adjust the light intensity corresponding to the λi band to a standard sunlight, the light intensity of the corresponding bands of other battery units remains unchanged, and then read the current value I through the electronic load i2 ; S4, I i =I i2 ‑I i1 is the short-circuit current of the ith battery cell measured; S5, repeating steps S2-S4 until the short-circuit current of each battery cell is measured.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic components, and in particular to a testing method and system for stacked solar cells. Background Art

[0002] With the continuous development of solar cell technology, tandem solar cells have gradually become mainstream. Tandem solar cells are a type of solar cell composed of multiple solar cell units stacked together. Its structure is different from that of traditional solar cells. Traditional solar cells have only one cell unit, while tandem solar cells are composed of multiple cells stacked and connected in series. This structural design makes the conversion efficiency of tandem solar cells higher and more stable. Due to the characteristics of tandem cells, when using traditional methods for IV testing, only the short-circuit current of the entire battery can be tested, and it is difficult to obtain the short-circuit current of each cell unit. Summary of the invention

[0003] In order to solve the problems raised in the above background technology, the technical solution adopted by the present invention is:

[0004] A method for testing a stacked solar cell, for a stacked solar cell composed of n battery units, n≥2, the spectral response band of any i-th battery unit is represented by λi, 1≤i≤n, a solar simulator capable of adjusting spectra of different bands respectively is used, and the method comprises the following steps:

[0005] S1. Place the stacked solar cell to be tested at the test position of the solar simulator, and connect the positive and negative electrodes of the stacked solar cell to be tested to the electronic load;

[0006] S2. When testing the i-th battery cell, adjust the light intensity corresponding to the λi band to zero, and adjust the light intensity of the corresponding bands of other battery cells to no less than two standard sunlight, and then read the current value I through the electronic load. i1 ;

[0007] S3, adjust the light intensity corresponding to the λi band to a standard sunlight, and keep the light intensity of the corresponding bands of other battery cells unchanged, and then read the current value I through the electronic load i2 ;

[0008] S4,I i =I i2 -I i1 That is, the short-circuit current of the i-th battery cell measured;

[0009] S5. Repeat steps S2-S4 until the short-circuit current of each battery cell is measured.

[0010] In some embodiments, in step S2, when testing the i-th battery cell, the light intensity corresponding to the λi band is adjusted to zero, and the light intensity of the corresponding bands of other battery cells is adjusted to three standard sunlights.

[0011] Another aspect of the present invention provides a test system for tandem solar cells, which adopts the above-mentioned test method for tandem solar cells and includes a solar simulator and an electronic load;

[0012] The solar simulator includes a light box, an LED light source system, a light homogenization system and a collimating lens;

[0013] The light box is a rectangular parallelepiped, and the LED light source system includes a plurality of LED light modules, which are divided into five groups. The five groups of LED light modules are respectively arranged on the upper part of the light box and on the front, rear, left and right sides;

[0014] The light homogenization system is arranged at the light outlet of the lower surface of the light box, and is used to mix and evenly process the light output by the LED light source system;

[0015] The collimating lens is arranged in the light path outside the light box, and is used for collimating the light output by the light homogenizing system and then outputting it to the test position.

[0016] In some embodiments, four filters are further arranged in the light box, and the four filters are respectively arranged in the light paths of the four groups of LED light modules on the inner side of the light box;

[0017] The filter is used to reflect light of a specific wavelength band. Each filter is tilted inward from top to bottom. The light output by the four groups of LED light modules on the side is respectively tilted to illuminate the corresponding filter and reaches the uniform light system after reflection.

[0018] The light output by a group of LED lamp modules on the upper part of the light box reaches the light uniforming system vertically downward.

[0019] In some embodiments, the LED light source system includes thirty LED lamp modules, and the thirty LED lamp modules are divided into five groups, each group including six LED lamp modules.

[0020] In some embodiments, the power of a single LED lamp module is 50-100W, different LED lamp modules correspond to different spectral bands, and multiple LED lamp modules together cover the 300-1200nm band.

[0021] In some embodiments, each LED lamp module includes an LED module, a heat sink and a focusing lens;

[0022] The heat sink is installed on the back of the LED module to achieve heat dissipation of the LED module;

[0023] The condenser lens is installed on the front of the LED module and is used to condense the light output by the LED module.

[0024] In some embodiments, each LED light module is configured with an independent constant current source and a control circuit, and the size of each constant current source can be adjusted individually, thereby adjusting the intensity of the light output by the corresponding LED light source module.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The test method of the laminated solar cell provided by the present invention can conveniently measure the short-circuit current of each battery unit. In addition, the test system of the laminated solar cell provided by the present invention sets five groups of LED light modules in different directions, each group of LED light modules is formed by a combination of multi-channel high-power LED arrays of different bands, and matches a unique optical path structure, which is conducive to ensuring reliable and stable lighting; and multiple bands are adjustable, by adjusting the current size of the LED light module corresponding to each band, the final output spectrum is accurately adjusted, so that the spectrum matching degree of the light spot reaches A+ level or above, and the test can be completed accurately according to the aforementioned test method of the laminated solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the internal structure of a solar simulator in a test system for tandem solar cells provided by the present invention;

[0028] Figure 2 This is a schematic diagram of the light path of a solar simulator;

[0029] Figure 3 Schematic diagram of an LED lamp module.

[0030] Explanation of the accompanying drawings: 1. Light box; 2. LED light module; 3. Light homogenization system; 4. Collimating lens; 5. Filter; 6. LED module; 7. Radiator; 8. Focusing lens. DETAILED DESCRIPTION

[0031] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following further describes how the present invention is implemented in conjunction with the accompanying drawings and specific implementation methods.

[0032] The present invention provides a testing method for a stacked solar cell. For a stacked solar cell composed of n battery units, n≥2, the spectral response band of any i-th battery unit is represented by λi, 1≤i≤n, and a solar simulator capable of adjusting spectra of different bands is used, and the method comprises the following steps:

[0033] S1. Place the stacked solar cell to be tested at the test position of the solar simulator, and connect the positive and negative electrodes of the stacked solar cell to be tested to the electronic load;

[0034] S2. When testing the i-th battery cell, adjust the light intensity corresponding to the λi band to zero, and adjust the light intensity of the corresponding bands of other battery cells to no less than two standard sunlights, preferably three standard sunlights, and then read the current value I through the electronic load. i1 ;

[0035] S3, adjust the light intensity corresponding to the λi band to a standard sunlight, and keep the light intensity of the corresponding bands of other battery cells unchanged, and then read the current value I through the electronic load i2 ;

[0036] S4,I i =I i2 -I i1 That is, the short-circuit current of the i-th battery cell measured;

[0037] S5. Repeat steps S2-S4 until the short-circuit current of each battery cell is measured.

[0038] The measurement principle is as follows: It can be understood that the short-circuit current of the solar cell is proportional to the radiation intensity, and the multiple current units of the stacked solar cell are connected in series, and the overall current is determined by the current unit with the smallest current.

[0039] Therefore, when measuring the short-circuit current of the ith battery cell, the light intensity corresponding to the λi band is first adjusted to zero, and the light intensity of the corresponding bands of other battery cells is adjusted to three standard sunlights; it can be understood that although the light intensity corresponding to the λi band is zero, the ith battery cell may still output a smaller current under the influence of other bands of light; and at this time, because the other battery cells receive the irradiation of three standard sunlights, the output current must be greater than the current of the ith battery cell. Because the multiple current units of the stacked solar cell are in series, the overall current is determined by the current unit with the smallest current, so the current value I read by the electronic load at this time i1 That is, the current output by the i-th battery cell in this case.

[0040] Next, the light intensity corresponding to the λi band is adjusted to a standard sunlight, and the light intensity of the corresponding bands of other battery cells remains unchanged. At this time, the current output by other battery cells is still greater than the current of the i-th battery cell, so the current value I read by the electronic load i2 is the current output by the i-th battery cell in this case; and I i2 It consists of two parts: the current I generated by light in other bands i1; The current generated by a standard sunlight in the λi band, that is, the short-circuit current I of the i-th battery cell i . Therefore I i =I i2 -I i1 That is the short-circuit current of the i-th battery cell.

[0041] Similarly for other battery cells, the above method can be used to conveniently measure the short-circuit current of each battery cell.

[0042] On the other hand, the present invention provides a testing system for laminated solar cells, which adopts the above-mentioned testing method for laminated solar cells and includes a solar simulator and an electronic load; the solar simulator includes a light box 1, an LED light source system, a uniform light system 3 and a collimating lens 4; the light box 1 is a rectangular parallelepiped, and the LED light source system includes a plurality of LED light modules 2, and the plurality of LED light modules 2 are divided into five groups, and the five groups of LED light modules 2 are respectively arranged on the upper part of the interior of the light box 1 and on the four sides of the front, rear, left and right; the uniform light system 3 is arranged at the light outlet of the lower surface of the light box 1, and is used to mix and evenly process the light output by the LED light source system; the collimating lens 4 is arranged in the light path outside the light box 1, and is used to collimate the light output by the uniform light system 3 and output it to the test position.

[0043] Preferably, four filters 5 are also provided in the light box 1, and the four filters 5 are respectively arranged on the optical paths of the four groups of LED light modules 2 on the inner side of the light box 1; the filters 5 are used to reflect light of a specific band, and each filter 5 is inclined inward from top to bottom. The light output by the four groups of LED light modules 2 on the side are respectively inclined to illuminate the corresponding filters 5, and reach the uniform light system 3 after reflection; the light output by a group of LED light modules 2 on the upper part of the light box 1 reaches the uniform light system 3 vertically downward.

[0044] In a specific embodiment, the LED light source system includes thirty LED lamp modules 2 , and the thirty LED lamp modules 2 are divided into five groups, each of which includes six LED lamp modules 2 .

[0045] In addition, the power of a single LED lamp module 2 is 50-100W, different LED lamp modules 2 correspond to different spectral bands, and multiple LED lamp modules 2 together cover the 300-1200nm band.

[0046] In this embodiment, the light emitted from the LED lamp module 2 in five directions is reflected into the range of the light homogenization system 3 through different filters 5, and then a light spot with uniformity of grade A+ can be obtained through the light homogenization system 3 and the collimating lens 4.

[0047] Further references Figure 3As shown, preferably, each LED lamp module 2 includes an LED module 6, a heat sink 7 and a focusing lens 8; the heat sink 7 is installed on the back of the LED module 6 to achieve heat dissipation of the LED module 6; the focusing lens 8 is installed on the front of the LED module 6 to converge the light output by the LED module 6.

[0048] Preferably, each LED lamp module 2 is equipped with an independent constant current source and a control circuit, and the size of each constant current source can be adjusted individually, so as to accurately adjust the intensity of the light output by the corresponding LED light source module. It can be understood that in step S2 of the aforementioned test method for laminated solar cells, when it is necessary to adjust the light intensity of a certain band, the light intensity can be accurately adjusted by adjusting the current size of the constant current source of the LED lamp module 2 of the corresponding band.

[0049] The multi-channel LED steady-state solar simulator system provided by the present invention has five groups of LED lamp modules 2 arranged in different directions, each group of LED lamp modules 2 is formed by a combination of multi-channel high-power LED arrays of different bands, and matched with a unique optical path structure, which is conducive to ensuring reliable and stable lighting; and multiple bands are adjustable, by adjusting the current size of the LED lamp module 2 corresponding to each band, the final output spectrum is accurately adjusted, so that the spectral matching degree of the light spot reaches A+ level or above, and the test can be completed accurately according to the aforementioned test method of the laminated solar cell.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for testing a tandem solar cell, characterized in that: For a stacked solar cell composed of n battery units, n≥2, the spectral response band of any i-th battery unit is represented by λi, 1≤i≤n, and a solar simulator capable of adjusting spectra of different bands is used, and the steps are as follows: S1. Place the stacked solar cell to be tested at the test position of the solar simulator, and connect the positive and negative electrodes of the stacked solar cell to be tested to the electronic load; S2. When testing the i-th battery cell, adjust the light intensity corresponding to the λi band to zero, and adjust the light intensity of the corresponding bands of other battery cells to no less than two standard sunlight, and then read the current value I through the electronic load. i1 ; S3, adjust the light intensity corresponding to the λi band to a standard sunlight, and keep the light intensity of the corresponding bands of other battery cells unchanged, and then read the current value I through the electronic load i2 ; S4,I i =I i2 -I i1 That is, the short-circuit current of the i-th battery cell measured; S5. Repeat steps S2-S4 until the short-circuit current of each battery cell is measured.

2. The method for testing a tandem solar cell according to claim 1, characterized in that: In step S2, when testing the i-th battery cell, the light intensity corresponding to the λi band is adjusted to zero, and the light intensity of the corresponding bands of other battery cells is adjusted to three standard sunlights.

3. A testing system for tandem solar cells, characterized in that: A method for testing a tandem solar cell according to any one of claims 1 to 2, comprising a solar simulator and an electronic load; The solar simulator comprises a light box (1), an LED light source system, a light homogenization system (3) and a collimating lens (4); The light box (1) is a rectangular parallelepiped, and the LED light source system comprises a plurality of LED light modules (2), wherein the plurality of LED light modules (2) are divided into five groups, and the five groups of LED light modules (2) are respectively arranged at the upper part of the interior of the light box (1) and at the front, rear, left and right sides; The light homogenization system (3) is arranged at the light output position of the lower surface of the light box (1) and is used to mix and homogenize the light output by the LED light source system; The collimating lens (4) is arranged in the light path outside the light box (1) and is used to collimate the light output by the light homogenizing system (3) and then output it to the test position.

4. The test system for tandem solar cells according to claim 3, characterized in that: Four filters (5) are also arranged in the light box (1), and the four filters (5) are respectively arranged on the light paths of the four groups of LED light modules (2) on the inner side of the light box (1); The filter (5) is used to reflect light of a specific wavelength band, and each filter (5) is inclined inward from top to bottom. The light output by the four groups of LED light modules (2) on the side is respectively inclined to illuminate the corresponding filter (5) and reach the uniform light system (3) after being reflected; Light outputted by a group of LED light modules (2) located at the upper part of the light box (1) reaches the light homogenization system (3) vertically downward.

5. The test system for tandem solar cells according to claim 3, characterized in that: The LED light source system comprises thirty LED lamp modules (2), and the thirty LED lamp modules (2) are divided into five groups, each group comprising six LED lamp modules (2).

6. The test system for tandem solar cells according to claim 3, characterized in that: The power of a single LED light module (2) is 50-100W, different LED light modules (2) correspond to different spectral bands, and a plurality of LED light modules (2) together cover the 300-1200nm band.

7. The test system for tandem solar cells according to claim 3, characterized in that: Each LED lamp module (2) comprises an LED module (6), a heat sink (7) and a focusing lens (8); The heat sink (7) is mounted on the back of the LED module (6) and is used to dissipate heat from the LED module (6); The condenser lens (8) is mounted on the front of the LED module (6) and is used to condense the light output by the LED module (6).

8. The test system for tandem solar cells according to claim 3, characterized in that: Each LED light module (2) is equipped with an independent constant current source and a control circuit. The size of each constant current source can be adjusted individually, thereby adjusting the intensity of the light output by the corresponding LED light source module.

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