JP2017158297A - Device for evaluating solar cell and method for manufacturing solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaluation device capable of quantitatively evaluating a rate-limiting degree of an element cell sensitive to a medium wavelength region in a multijunction solar cell having three element cells with different sensitivity wavelength regions.SOLUTION: A light irradiation device can irradiate pseudo sunlight of a condition corresponding to one state of sunlight, and can irradiate first limiting light preferentially limiting irradiance at the maximum absorption wavelength of a second element cell with respect to the pseudo sunlight, and, when evaluating the solar cell, is configured to directly or indirectly compare a current value when the solar cell is irradiated with the pseudo sunlight and a current value when the solar cell is irradiated with the first limiting light.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a solar cell evaluation apparatus and a solar cell manufacturing method.

Conventionally, a solar cell is evaluated using a solar simulator that combines one or more light sources, and a standard state of “air mass 1.5, 1000 W / m ² , 25 ° C.” that is a state of sunlight (Standard Test). It is often performed by creating simulated sunlight that satisfies the condition corresponding to Condition (STC). And this solar cell is evaluated by, for example, irradiating the solar cell with pseudo-sunlight that satisfies the conditions corresponding to STC, and evaluating the solar cell characteristics such as short circuit current, open potential, curve factor, conversion efficiency of the solar cell. (For example, Patent Document 1).

By the way, in recent years, a multi-junction solar cell in which three or more element cells having different relative spectral sensitivities are joined has been developed (for example, Patent Document 2). This multi-junction solar cell can perform photoelectric conversion in a wide wavelength region by performing photoelectric conversion in each element cell, and can secure high conversion efficiency.
The solar cell described in Patent Document 2 is a three-junction in which a bottom cell (crystalline silicon germanium photoelectric conversion unit), a middle cell (crystalline silicon photoelectric conversion unit), and a top cell (amorphous silicon photoelectric conversion unit) are connected in series. It is a solar cell, and the bottom cell, middle cell, and top cell have spectral sensitivity in the short wavelength region, medium wavelength region, and long wavelength region, respectively, and can generate power by absorbing light in each wavelength region. ing.

JP 2006-135196 A International Publication No. 2013/035686

Since each element cell is connected in series, the output of the three-junction solar cell depends on the output characteristics of the element cell that is rate limiting. Therefore, the current balance of each element cell is important for the design of this three-junction solar cell.
Here, for example, in sunlight in Tokyo, the irradiance in the short wavelength region is often stronger than that in other wavelength regions as compared with the conditions corresponding to STC. Therefore, in consideration of the system output coefficient, a current balance in which rate limiting occurs on the top cell side having an absorption wavelength in a short wavelength region is preferable.

However, in general, simulated sunlight adjusted by a solar simulator is considered extremely difficult to completely reproduce sunlight.
For example, the pseudo-sunlight generated by a certain solar simulator takes a spectrum as shown in FIG. 9 and has an irradiance of 3 than that of actual sunlight in the middle wavelength range of about 550 nm to 750 nm, which is the absorption wavelength range of the middle cell. % -7% higher.
In such a case, in the evaluation using the pseudo sunlight that sets the conditions corresponding to STC, the middle cell is overestimated as compared with the case where the sunlight is irradiated, and the current balance of each element cell cannot be accurately determined. There was a problem.

  Therefore, the present invention has an object of providing an evaluation device capable of quantitatively evaluating the rate-determining rate of an element cell having sensitivity in the middle wavelength region in a multijunction solar cell having three element cells having different sensitivity wavelength regions. And Moreover, it aims at providing the manufacturing method of the solar cell which can mass-produce the solar cell which ensured fixed quality using the said evaluation apparatus.

  The invention described in claim 1 for solving the above-described problem is an evaluation apparatus for a solar cell in which a first element cell, a second element cell, and a third element cell are connected in series. The maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the element cell is shorter than the maximum absorption wavelength of the second element cell, and the maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the third element cell is In a solar cell evaluation device that takes a longer wavelength than the maximum absorption wavelength of the second element cell, the solar cell has a light irradiation device, and the light irradiation device irradiates pseudo-sunlight under a condition corresponding to one state of sunlight. It is possible to irradiate the first limiting light that preferentially limits the irradiance at the maximum absorption wavelength of the second element cell at a predetermined ratio with respect to the pseudo-sunlight, and evaluate the solar cell. When the solar light is A short-circuit current value when irradiated to an evaluation apparatus for the photovoltaic devices, characterized in that the first limiting light to compare the short-circuit current values directly or indirectly when irradiated to the solar cell.

  Here, “directly or indirectly comparing current values” includes not only a case where current values are compared but also a value obtained by adding or integrating a constant term to current values.

According to the configuration of the present invention, the maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the first element cell is shorter than the maximum absorption wavelength of the second element cell, and the relative spectral sensitivity of the third element cell is The maximum absorption wavelength corresponding to the maximum value is longer than the maximum absorption wavelength of the second element cell. That is, the maximum absorption wavelength of each element cell increases in the order of the first element cell, the second element cell, and the third element cell. The second element cell includes the first element cell, the second element cell, and the third element cell. The maximum absorption wavelength is taken in the middle wavelength region of the cell.
According to the configuration of the present invention, for example, the following (1) and (2) are performed.
(1) The short circuit current value which is one of the whole performance of a solar cell is calculated by irradiating a solar cell with pseudo sunlight.
(2) The second element cell is intentionally controlled by irradiating the solar cell with the first limiting light in which light is preferentially limited at a predetermined ratio at the absorption wavelength of the second element cell with respect to the pseudo-sunlight. Then, the short-circuit current value in which the component of the second element cell is mainly reflected is calculated.
And each short circuit current value computed by these (1) and (2) is compared, and the ratio with respect to the short circuit current value by the pseudo sunlight of the short circuit current value by the 1st limiting light is in the maximum absorption wavelength of the 2nd element cell. If it is smaller than the ratio of the first limiting light to the pseudo-sunlight, the solar cell that is the object of evaluation is less affected by limiting the pseudo-sunlight, and the second element cell becomes the dominant factor of the short-circuit current value. I understand that. Therefore, it can be estimated that the second element cell is rate-limiting.
Moreover, according to the structure of this invention, by comparing the ratio with respect to the pseudo-sunlight of the 1st limiting light in the maximum absorption wavelength of a 2nd element cell, and the decreasing rate with respect to the short circuit current value by pseudo-sunlight, it is 2nd element. It is also possible to estimate the rate limit of the cell.

  The invention according to claim 2 is characterized in that, at the maximum absorption wavelength of the second element cell, the irradiance of the first limiting light is 60% or less of the irradiance of pseudo-sunlight. It is an evaluation apparatus of the described solar cell.

  According to the configuration of the present invention, it is easy to extract only the characteristics of the second element cell from the solar battery.

  The invention according to claim 3 has a limiting filter that limits the irradiance to the pseudo-sunlight, wherein the maximum absorption wavelength of the second element cell is in a wavelength range of 550 nm to 750 nm, 3. The solar cell evaluation apparatus according to claim 1, wherein the limiting filter has a total transmittance of 60% or less within a range of 50 nm from a maximum absorption wavelength of the second element cell. 4.

According to the configuration of the present invention, the maximum absorption wavelength of the second element cell is in the wavelength range of 550 nm to 750 nm, and is, for example, large between sunlight in Tokyo and pseudo-sunlight under conditions corresponding to STC. This is the range where errors occur. In other words, when a condition corresponding to one state of sunlight is set to a condition corresponding to STC, this is a range where a large error occurs.
Therefore, according to the configuration of the present invention, the limiting filter has a transmittance in the range of ± 50 nm of the maximum absorption wavelength of the second element cell of 60% or less, and in a wavelength region near the maximum absorption wavelength of the second element cell. It is greatly restricted. Therefore, the short-circuit current value due to the first limiting light largely reflects the component of the second element cell, and it is easy to extract the component of the second element cell, and to easily determine the rate limiting rate of the second element cell.

  By the way, the pseudo-sunlight generated by the solar simulator may be greatly deviated even in a short wavelength region depending on the type of solar simulator and its adjustment. For example, in the pseudo-sunlight spectrum in a solar simulator shown in FIG. 9, the main absorption of the top cell is shifted in the short wavelength region of 350 nm to 450 nm, although it is shifted from the maximum absorption wavelength of a general top cell. It overlaps with the wavelength, and the irradiance is about 10% to 20% higher than actual sunlight. For this reason, as in the prior art, when irradiating simulated sunlight with conditions equivalent to STC, the top cell is greatly evaluated compared to the case where sunlight is irradiated, and the current balance of each cell cannot be accurately determined. There is.

  Therefore, in the invention according to claim 4, the light irradiating device includes a short wavelength light having a peak on the short wavelength side with an irradiance of 650 nm or less and a long wavelength having a peak on the long wavelength side with an irradiance of more than 650 nm. The light can be irradiated independently, and the pseudo-sunlight can be irradiated by the mixed light of the short wavelength light and the long wavelength light, and the light irradiation device emits a first light beam. The second light beam condition for irradiating the second light beam can be implemented, and the first light beam has a longer ratio to the mixed light under a condition in which the ratio α1 of the long wavelength light to the mixed light corresponds to one state of the sunlight. The ratio α2 of the wavelength light is smaller than the ratio α3 of the long wavelength light to the mixed light under the condition that the ratio of the long wavelength light to the mixed light α2 is equivalent to one state of the sunlight. Is also big, The solar cell is irradiated with the first light beam and the second light beam according to the first light beam condition and the second light beam condition, and the current value under the first light beam condition and the current value under the second light beam condition are directly measured. The solar cell evaluation apparatus according to any one of claims 1 to 3, wherein the solar cell is evaluated in comparison with the target or indirectly.

According to the configuration of the present invention, a first light beam having a smaller ratio α1 of long-wavelength light to mixed light than pseudo-sunlight is irradiated to create a pseudo-rate-limiting state of the first element cell, and its short-circuit current value Further, the second light ray having a larger ratio α2 of the long-wavelength light to the mixed light than that of the artificial sunlight is irradiated to create a rate-limiting state of the third element cell in a pseudo manner to obtain the short circuit current value. Then, these are compared, and if the short-circuit current value in the first light beam is larger than the short-circuit current value in the second light beam, the first element cell side is rate-limiting, and the short-circuit current value in the first light beam is second. If it is smaller than the short-circuit current value with the light beam, it can be estimated that there is a rate-limiting on the third element cell side.
Further, according to the configuration of the present invention, by comparing the short-circuit current value in the first light beam and the short-circuit current value in the second light beam, the relative rate of the first element cell and the third element cell can be determined. It can also be estimated.

  In the invention according to claim 5, the difference between the ratio α1 of the long wavelength light to the mixed light in the first light condition and the ratio α3 of the long wavelength light to the mixed light in a condition corresponding to one state of the sunlight is: 5. The difference between the ratio α2 of the long wavelength light to the mixed light in the second light condition and the ratio α3 of the long wavelength light to the mixed light in a condition corresponding to one state of the sunlight is approximately equal to 5. It is an evaluation apparatus of the solar cell as described in.

  Here, “substantially equal” means that the difference is within ± 0.2%. Of course, the same case is included.

  According to the configuration of the present invention, the difference between the first light ray ratio α1 and the pseudo-sunlight ratio α3 (α3-α1) is the difference between the second light ray ratio α2 and the pseudo-sunlight ratio α3 (α3-α2). Since they are substantially equal, the pseudo rate-limiting state can be set to the same level on condition, and the rate-limiting rate of the first element cell and the third element cell can be easily compared.

  According to a sixth aspect of the present invention, in the first light beam, the ratio α1 of the long wavelength light to the mixed light is 0.96 of the ratio α3 of the long wavelength light to the mixed light under a condition corresponding to one state of the sunlight. In the second light ray, the ratio α2 of the long wavelength light to the mixed light is 1.04 or less of the ratio α3 of the long wavelength light to the mixed light under the condition corresponding to one state of the sunlight. It is an evaluation apparatus of the solar cell of Claim 4 or 5 characterized by the above-mentioned.

  According to the configuration of the present invention, the rate limiting rate of the first element cell and the third element cell can be estimated more accurately.

  The invention according to claim 7 is a solar cell evaluation apparatus in which a first element cell, a second element cell, and a third element cell are connected in series, and the maximum relative spectral sensitivity of the first element cell is The maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the third element cell, the maximum absorption wavelength corresponding to the value being shorter than the maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the second element cell Is a solar cell evaluation device that takes a wavelength longer than the maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the second element cell, and has a light irradiation device, and the light irradiation device has an irradiance of 650 nm or less. The short wavelength light having a peak on the short wavelength side and the long wavelength light having a peak on the long wavelength side with an irradiance of more than 650 nm can be independently irradiated, and the short wavelength light and the long wavelength light are mixed. Light can be irradiated to the light receiving surface of the solar cell The light irradiation device can irradiate pseudo-sunlight with a condition corresponding to one state of sunlight by the mixed light, and the light irradiation device has a first light beam condition for irradiating a first light beam, The second light ray condition for irradiating the second light ray can be implemented, and the first light ray has a long wavelength with respect to the mixed light under a condition in which a ratio α1 of the long wavelength light to the mixed light corresponds to one state of the sunlight. The ratio of the long wavelength light to the mixed light is less than the ratio α3 of the long wavelength light to the mixed light in a condition corresponding to one state of the sunlight. The solar cell is irradiated with the first light beam and the second light beam under the first light beam condition and the second light beam condition, and the current value under the first light beam condition and the second light beam condition are Compare the current value directly or indirectly The solar cell evaluation apparatus is characterized by evaluating the solar cell.

  According to the configuration of the present invention, it is possible to estimate the relative rate-limiting position and rate-limiting rate of the first element cell and the third element cell.

  The invention according to claim 8 is a method of manufacturing a solar cell in which a first element cell, a second element cell, and a third element cell are connected in series, and the maximum relative spectral sensitivity of the first element cell is The maximum absorption wavelength corresponding to the value is shorter than the maximum absorption wavelength of the second element cell, and the maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the third element cell is the maximum absorption wavelength of the second element cell. It is a manufacturing method of the solar cell taken on the longer wavelength side, Comprising: It evaluated using the evaluation apparatus in any one of Claims 1-6, and the short circuit current when the said pseudo-sunlight is irradiated to the said solar cell A prescription is adjusted so that the ratio of the short-circuit current value when the light receiving surface of the solar cell is irradiated with the first limiting light with respect to the value is 73% or more and 75% or less. is there.

  According to the method of the present invention, it is possible to adjust the prescription at the time of manufacture according to the evaluation result, and it is possible to manufacture a large number of solar cells of a certain quality. In addition, according to the method of the present invention, defective products are less likely to occur, and the yield can be improved as compared with the conventional method.

  The invention according to claim 9 is a method of manufacturing a solar cell in which a first element cell, a second element cell, and a third element cell are connected in series, and the maximum relative spectral sensitivity of the first element cell is The maximum absorption wavelength corresponding to the value is shorter than the maximum absorption wavelength of the second element cell, and the maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the third element cell is the maximum absorption wavelength of the second element cell. It is a manufacturing method of the solar cell taken on the longer wavelength side, and is evaluated using the evaluation device according to any one of claims 4 to 6, and the current value when the solar cell is irradiated with the pseudo-sunlight The ratio of the current value when the solar cell is irradiated with the first limiting light with respect to is from 73% to 75%, and the first ray and the second ray of the first ray condition and the second ray condition The second light condition when the solar cell is irradiated with The ratio of the current value in the first light beam condition with respect to the current value of a method of manufacturing a solar cell, which comprises adjusting the formulated to be 1.02 or more.

  According to the method of the present invention, solar cells can be manufactured by adjusting the prescription at the time of manufacture according to the evaluation results, and high-quality solar cells can be manufactured in large quantities. In addition, according to the method of the present invention, defective products are less likely to occur, and the yield can be improved as compared with the conventional method.

According to the evaluation apparatus of the present invention, in a multijunction solar cell having three element cells having different sensitivity wavelength regions, the rate limiting factor of the element cells having sensitivity in the middle wavelength region can be quantitatively evaluated.
According to the manufacturing method of the present invention, it is possible to mass-produce solar cells that ensure a certain quality.

It is a schematic diagram of the evaluation apparatus of 1st Embodiment of this invention. It is explanatory drawing of the limiting filter used for the evaluation apparatus of FIG. 1, the upper figure is a graph showing the transmittance | permeability of a filter, and the lower figure is a graph showing the relative spectral sensitivity of each element cell of a solar cell. It is the graph which plotted the short circuit current with respect to the illumination intensity ratio of the long wavelength light with respect to mixed light. It is the graph which plotted short circuit current ratio Rb with respect to short circuit current ratio Ra. It is sectional drawing which showed typically the solar cell suitable for evaluation with the evaluation apparatus of FIG. 1, and hatching is abbreviate | omitted in order to make an understanding easy. It is the graph which plotted the short circuit current with respect to the illumination intensity ratio of the long wavelength light with respect to the mixed light of the solar cell of Examples 1-4. It is the graph which plotted short circuit current ratio Rb with respect to short circuit current ratio Ra of the solar cell of Examples 5-8. It is the graph which plotted short circuit current ratio Rb with respect to short circuit current ratio Ra of the solar cell of Examples 9-12. It is the figure which compared the spectrum of sunlight at the time of using a certain solar simulator, and the spectrum of pseudo sunlight.

  Hereinafter, embodiments of the present invention will be described in detail. In the following description, physical properties are based on standard conditions (25 ° C., 1 atm) unless otherwise specified.

The solar cell evaluation apparatus 1 according to the first embodiment of the present invention evaluates the performance of a solar cell 100 including three element cells 51, 52, and 53.
Specifically, the evaluation apparatus 1 is an apparatus that specifies an element cell that is rate-limiting among the element cells 51, 52, and 53, and further evaluates how much the element cell is rate-limiting.

  As shown in FIG. 1, the evaluation device 1 includes a light source device 2, a light transmission member 5, a limiting filter 6, a stage 7, a spectral sensitivity measurement device 8, and a current / voltage measurement device 10.

The light source device 2 is a light irradiation device that irradiates the solar cell 100 with light, and can irradiate the irradiation light as pulsed light having a light emission time of about 0.001 seconds to 1.0 seconds.
The light source device 2 is a light source that combines a plurality of lamps, and can adjust the irradiation light to a desired irradiance. Specifically, the light source device 2 includes a short wavelength light source 11 and a long wavelength light source 12, and by combining these, it is possible to irradiate pseudo sunlight under a condition corresponding to one state of sunlight. Yes.

The short wavelength light source 11 is a light source capable of emitting short wavelength light 15 having a peak of irradiance in a wavelength region of 650 nm or less.
The long wavelength light source 12 is a long wavelength light 16 having a peak of irradiance in a wavelength region exceeding 650 nm, and can irradiate the long wavelength light 16 having a peak of irradiance on the longer wavelength side than the short wavelength light source 11. Light source.
A xenon lamp is used as the short wavelength light source 11 and a halogen lamp is used as the long wavelength light source 12.
The light source device 2 can irradiate the solar cell 100 with the mixed light 17 of the short wavelength light 15 and the long wavelength light 16.

The light transmission member 5 is a transparent plate-like member, and is a member that transmits light from the light source device 2 side to the limiting filter 6 side.
The light transmissive member 5 is not particularly limited as long as it has translucency, and a translucent plate such as an acrylic plate or a glass plate can be adopted.

The limiting filter 6 is a filter that preferentially limits the irradiance (illuminance when viewed from the limiting filter 6 side) in a specific wavelength range. Specifically, the limiting filter 6 is a color filter that passes a specific wavelength range and limits the specific wavelength range.
Details of the limiting filter 6 will be described later.

  The stage 7 is a base for fixing the solar cell 100 to be irradiated with light, and can be fixed so that the light receiving surface of the solar cell 100 faces the incident side.

  The spectral sensitivity measuring device 8 is a device that irradiates the solar cell 100 with monochromatic light of constant energy and constant photons having no wavelength dependence, and measures the spectral sensitivity characteristics and quantum efficiency of the element cells 51, 52, and 53.

  The current-voltage measuring device 10 is a device that measures the current-voltage characteristics of the solar cell 100.

As shown in FIG. 5, the solar cell 100 includes a first element cell 51 (hereinafter also referred to as a top cell 51), a second element cell 52 (hereinafter also referred to as a middle cell 52), from the light receiving surface side (light incident side), and A third element cell 53 (hereinafter also referred to as a bottom cell 53) is connected in series.
As shown in FIG. 2, the solar cell 100 includes three element cells 51, 52, and 53 having different maximum absorption wavelengths corresponding to the maximum value of relative spectral sensitivity. That is, the element cells 51, 52 and 53 have different maximum peak positions when plotting the relative spectral sensitivity with respect to each absorption wavelength and graphing.

Specifically, as shown in FIG. 2, the first element cell 51 has a maximum peak on the short wavelength side as compared to the other element cells 52 and 53. The second element cell 52 has a maximum peak between the maximum peak of the first element cell 51 and the maximum peak of the third element cell 53. The third element cell 53 has a maximum peak on the longer wavelength side than the second element cell 52.
That is, the relative spectral sensitivity graph of the first element cell 51 is shifted to the shorter wavelength side than the relative spectral sensitivity graph of the second element cell 52, and the relative spectral sensitivity graph of the third element cell 53 is The relative spectral sensitivity graph of the two-element cell 52 is shifted to the longer wavelength side.

The maximum absorption wavelength λ 1 corresponding to the maximum value of the relative spectral sensitivity of the first element cell 51 is 100 nm or more shorter than the maximum absorption wavelength λ 2 corresponding to the maximum value of the relative spectral sensitivity of the second element cell 52.
The maximum absorption wavelength λ3 corresponding to the maximum value of the relative spectral sensitivity of the third element cell 53 is 100 nm or more longer than the maximum absorption wavelength λ2 corresponding to the maximum value of the relative spectral sensitivity of the second element cell 52.

The graph of the relative spectral sensitivity of the first element cell 51 and the graph of the relative spectral sensitivity of the second element cell 52 include an intersection A that intersects each other as shown in FIG.
The intersection A is an intersection of two adjacent element cells 51 and 52, which is longer than the maximum absorption wavelength λ1 of the first element cell 51 and shorter than the maximum absorption wavelength λ2 of the second element cell 52. On the wavelength side. That is, the intersection point A is a boundary point at which the dominant factor is switched between the first element cell 51 and the second element cell 52. On the short wavelength side from the intersection point A, the light absorption in the first element cell 51 is reduced. The light absorption in the second element cell 52 becomes dominant, and the light absorption in the second element cell 52 becomes more dominant than the light absorption in the first element cell 51 on the longer wavelength side than the intersection A.

In addition, the graph of the relative spectral sensitivity of the second element cell 52 and the graph of the relative spectral sensitivity of the third element cell 53 include an intersection B that intersects with each other.
The intersection B is an intersection of two adjacent element cells 52 and 53, which is longer than the maximum absorption wavelength λ2 of the second element cell 52 and shorter than the maximum absorption wavelength λ3 of the third element cell 53. On the wavelength side. That is, the intersection point B is a boundary point at which the dominant factor is switched between the second element cell 52 and the third element cell 53, and light absorption in the second element cell 52 is shorter on the shorter wavelength side than the intersection point B. The light absorption in the third element cell 53 is more dominant than the light absorption in the third element cell 53, and the light absorption in the third element cell 53 is more dominant than the light absorption in the second element cell 52 on the longer wavelength side than the intersection B.

Furthermore, the graph of the relative spectral sensitivity of the first element cell 51 and the graph of the relative spectral sensitivity of the third element cell 53 have intersections C that intersect each other.
The intersection point C is between the intersection point A and the intersection point B, and is between the maximum absorption wavelength λ1 of the first element cell 51 and the maximum absorption wavelength λ3 of the third element cell 53.
The detailed laminated structure of the solar cell 100 will be described later for convenience of explanation.

Here, the restriction filter 6 will be described in further detail.
The limiting filter 6 preferentially limits the irradiance in the wavelength region near the maximum absorption wavelength of the specific element cell. That is, the limiting filter 6 has a small transmittance in a wavelength region near the maximum absorption wavelength of a specific element cell.
In the limiting filter 6 of the present embodiment, as can be seen from FIG. 2, the irradiance in the vicinity of the maximum absorption wavelength λ2 of the second element cell 52 is the irradiance in the vicinity of the maximum absorption wavelengths λ1 and λ3 of the other element cells 51 and 53. It is limited compared to
That is, when the maximum absorption wavelengths of the first element cell 51, the second element cell 52, and the third element cell 53 are λ1, λ2, and λ3, the limiting filter 6 is the maximum of the second element cell 52 that is the restriction target. The transmittance at the absorption wavelength λ2 is smaller than the transmittance at the wavelengths λ1 and λ3.
As shown in FIG. 2, the limiting filter 6 of the present embodiment includes a second element cell 52 and a third element from the intersection A of the first element cell 51 and the second element cell 52 in the waveform of the second element cell 52. In the wavelength region up to the intersection B of the cell 53, the irradiance is preferentially lowered.

If the limiting filter 6 has a too low transmittance at the wavelength λ2, the photoelectric conversion characteristics of the solar cell 100 are greatly affected by light in a wavelength region other than the wavelength λ2, and thus the transmittance at the wavelength λ2 is 40%. The above is preferable. That is, the limiting filter 6 preferably has a limiting rate of 60% or less at the wavelength λ2.
From the viewpoint of distinguishing the element cell 52 to be restricted from the other element cells 51 and 53, the limiting filter 6 preferably has a transmittance of 60% or less at the wavelength λ2 and more preferably 55% or less. . That is, the limiting filter 6 preferably has a limiting rate of 40% or more at the wavelength λ2.
In the limiting filter 6, the difference between the transmittance at the wavelength λ2 and the transmittance at the wavelengths λ1 and λ3 is preferably 10% or more, and more preferably 20% or more.
Further, from the viewpoint of accurately extracting only the components of the second element cell 52, the limiting filter 6 preferably has a difference between the transmittance at the wavelength λ1 and the transmittance at the wavelength λ3 of 10% or less, and 7% or less. It is more preferable.
In the limiting filter 6 of the present embodiment, the entire transmittance within the range of the maximum absorption wavelength λ2 to 50 nm of the second element cell 52 is 60% or less, the transmittance at the wavelength λ1 is about 75%, and the transmittance at the wavelength λ2. Is about 55%, and the transmittance at the wavelength λ3 is about 80%.

  Then, the evaluation method of a solar cell is demonstrated.

The evaluation method of the present embodiment mainly includes three steps. That is, the evaluation method of the present embodiment includes a middle evaluation step for evaluating the rate limiting rate of the middle cell 52 (second element cell 52) of the solar cell 100, a top cell 51 (first element cell 51) of the solar cell 100, and It includes a top / bottom evaluation step for evaluating the relative rate of the bottom cell 53 (third element cell 53), and a comprehensive evaluation step for evaluation based on the results of the middle evaluation step and the top / bottom evaluation step.
Hereinafter, each process will be described in detail.

  The middle evaluation step is a step of preferentially limiting the absorption wavelength range of the middle cell 52 with the limiting filter 6 and making the middle cell 52 close to a pseudo rate-limiting state.

In this middle evaluation step, the solar light receiving surface of the solar cell 100 is irradiated with artificial sunlight under conditions (air mass 1.5, 1000 W / m ² , 25 ° C.) corresponding to a reference state (STC) which is one state of sunlight. Then, the current-voltage characteristic is measured, and the short-circuit current value Isc in pseudo sunlight under the condition corresponding to STC is calculated from the current-voltage characteristic.
In addition, the limiting filter 6 is used to irradiate the light-receiving surface of the solar cell 100 with the first limiting light under the first limiting condition in which the pseudo-sunlight corresponding to the STC is limited in irradiance by the limiting filter 6. The voltage characteristic is measured, and the short-circuit current value I1 with the first limiting light is calculated from the current-voltage characteristic.
And the short circuit current value Isc when irradiating the pseudo sunlight of the conditions equivalent to STC and the short circuit current value I1 when irradiating the 1st limiting light of 1st limiting conditions are compared.
Specifically, the ratio (Ra = I1 / Isc) of the short-circuit current value I1 when the first limiting light of the first limiting condition is irradiated to the short-circuit current value Isc when the pseudo-sunlight of the condition corresponding to STC is irradiated. ) Is calculated. Then, it is determined that the rate limiting rate of the middle cell 52 increases as the calculated short-circuit current ratio Ra decreases, and that the rate limiting rate of the middle cell 52 decreases as the calculated short-circuit current ratio Ra increases.

At this time, the first limiting light of the first limiting condition is a wavelength in the vicinity of the maximum absorption wavelength λ2 corresponding to the maximum peak of the relative spectral sensitivity of the middle cell 52 than the simulated sunlight of the condition corresponding to STC by the limiting filter 6 described above. The irradiance is narrowed down preferentially in the region, and the irradiance is the smallest at the maximum absorption wavelength λ 2 of the middle cell 52 among the maximum absorption wavelengths of the three element cells 51, 52, 53.
In the present embodiment, the first limiting light can be read from FIG. 2. When the relative spectral sensitivity with respect to each absorption wavelength is graphed in each element cell 51, 52, 53, the graph of the top cell 51 and the middle cell 52. The irradiance of the middle cell 52 is compared with the other element cells 51 and 52 in the wavelength range from the wavelength corresponding to the intersection A to the graph to the wavelength corresponding to the intersection B of the middle cell 52 graph and the bottom cell 53 graph. We narrow down preferentially.

In the top-bottom process, the mixing ratio of the short-wavelength light 15 and the long-wavelength light 16 is changed to bring the top cell 51 and the bottom cell 53 into a pseudo rate-limiting state, and the rate-limiting ratio of the top cell 51 and the bottom cell 53 is compared. It is a process to do.
The top-bottom process changes the mixing ratio of the short-wavelength light 15 and the long-wavelength light 16, and lowers the ratio of the long-wavelength light 16 to the ratio α3 of the long-wavelength light 16 to the mixed light 17 under conditions equivalent to STC. The first light beam measuring step of irradiating the light receiving surface of the solar cell 100 with the first light beam having the first light beam condition, and the light receiving surface of the solar cell 100 having the second light beam condition with the ratio of the long wavelength light 16 increased. 2nd light measurement process which irradiates to.
In the first light ray measuring step, the first light ray having a ratio α1 of the long wavelength light 16 to the mixed light 17 smaller than the ratio α3 of the long wavelength light 16 to the mixed light 17 under the condition corresponding to STC is used as the light receiving surface of the solar cell 100. The current-voltage characteristics are measured. Then, the short-circuit current value Iα1 for the first light beam is calculated from the current-voltage characteristics.
On the other hand, in the second light beam measurement step, the solar cell 100 receives a second light beam in which the ratio α2 of the long wavelength light 16 to the mixed light 17 is larger than the ratio α3 of the long wavelength light 16 to the mixed light 17 under a condition corresponding to STC. Irradiate the surface and measure the current-voltage characteristics. Then, the short-circuit current value Iα2 for the second light beam is calculated from the current-voltage characteristics.

In the first light measurement step of the top-bottom process of this embodiment, the ratio α1 of the long wavelength light 16 to the mixed light 17 is smaller by β than the ratio α3 of the long wavelength light 16 to the mixed light 17 under the condition corresponding to STC. A short circuit current value Iα1 is calculated for each first light beam under the first short wavelength condition and the second short wavelength condition in which the ratio α1 of the long wavelength light 16 to the mixed light 17 is smaller than the first short wavelength condition by β.
On the other hand, the second light beam measuring step includes a first long wavelength condition in which the ratio α1 of the long wavelength light 16 to the mixed light 17 is larger by β than the ratio α3 of the long wavelength light 16 to the mixed light 17 under the condition corresponding to STC. Then, the short-circuit current value Iα2 for each second light beam under the second long wavelength condition where the ratio α1 of the long wavelength light 16 to the mixed light 17 is larger by β than the first long wavelength condition is calculated.
Thereafter, as shown in FIG. 3, the second short wavelength condition (ratio α3-2β), the first short wavelength condition (ratio α3-β), the condition corresponding to STC (α3), and the first long wavelength condition (ratio α3 + β). , And plotting each short-circuit current value under the second long wavelength condition (ratio α3 + 2β), the waveform is a continuous mountain shape, and the first short wavelength condition and the first long wavelength condition are not measurement failure points. Check.

  After confirming that the first short wavelength condition and the first long wavelength condition are not measurement failure points, the short circuit current value Iα1 under the first short wavelength condition (ratio α3-β) and the short circuit under the first long wavelength condition (ratio α3 + β) The current value Iα2 is compared, and the ratio of the short circuit current value Iα1 under the short wavelength condition to the short circuit current value Iα2 under the first long wavelength condition (Rb = Iα1 / Iα2) is calculated. Then, it is determined that the rate limiting rate of the bottom cell 53 increases as the calculated short circuit current ratio Rb decreases, and the rate limiting rate of the top cell 51 increases as the calculated short circuit current ratio Rb increases.

In the comprehensive evaluation process, which element cell is rate-limiting is evaluated from the relationship between the short-circuit current ratio Ra calculated in the middle evaluation process and the short-circuit current ratio Rb calculated in the bottom-top evaluation process.
This point will be described with reference to FIG. For convenience of explanation, the computer does not actually plot the coordinates, but only the numerical values.

When the short-circuit current ratio Ra is smaller than the first threshold value and the short-circuit current ratio Rb is smaller than the second threshold value (measurement point 30), the comprehensive evaluation process is as follows. It is determined that the middle cell 52 is rate-limiting and that the middle cell 52 is rate-limiting on the bottom cell 53 side.
When the short-circuit current ratio Ra is smaller than the first threshold value and the short-circuit current ratio Rb is greater than or equal to the second threshold value (the II region on the upper left in FIG. 4) as the measurement result is the measurement point 31, the middle cell 52 is rate-limiting. In addition, it is determined that there is a rate-determining method on the top cell 51 side among the middle cells 52.
When the short circuit current ratio Ra is equal to or higher than the first threshold value and the short circuit current ratio Rb is smaller than the second threshold value (region III in the lower right in FIG. 4) as in the measurement point 32, the bottom cell 53 It is determined to be rate limiting.
When the short-circuit current ratio Ra is equal to or greater than the first threshold and the short-circuit current ratio Rb is equal to or greater than the second threshold as in the measurement point 33 (the upper right IV region in FIG. 4), the top cell 51 It is determined to be rate limiting.

Here, in the present embodiment, the first threshold value that is the reference for the rate-determining determination of the middle cell 52 is set to the transmittance of the limiting filter 6. That is, if the calculated short circuit current ratio Ra is smaller than the transmittance of the limiting filter 6, the middle cell 52 is rate limiting, and if the calculated short circuit current ratio Ra is equal to or higher than the transmittance of the limiting filter 6, the top cell 51 or the bottom cell 53. Is determined to be rate limiting.
Further, in the present embodiment, the second threshold value that is a reference for determining the rate limiting of the top cell 51 and the bottom cell 53 is set to 1. That is, if the calculated short-circuit current ratio Rb is 1 or more, it is determined that there is a rate-limiting on the top cell 51 side, and if the calculated short-circuit current ratio Rb is less than 1, it is determined that there is a rate-limiting on the bottom cell 53 side.

As described above, according to the evaluation method of the present embodiment, it is possible to determine the element cell that is rate limiting in the solar cell 100.
In addition, according to the evaluation method of the present embodiment, the rate limiting rate of each rate limiting cell can be calculated as a relative numerical value, so that it is easy to determine the rate limiting rate.

  Then, in this embodiment, the solar cell 100 is manufactured using the above-described evaluation apparatus. A method for manufacturing this solar cell will be described below. In particular, the solar cell evaluation process, which is one of the features of this embodiment, will be described with emphasis, and the remaining processes will be briefly described since they are the same as in the prior art.

First, the solar cell formation process which forms the solar cell 100 is implemented.
Specifically, the transparent insulating substrate 102 is introduced into a CVD apparatus, and the transparent electrode layer 103 is formed (transparent electrode layer forming step).

When the transparent electrode layer forming step is completed, each element cell 51, 52, 53 is formed by a CVD apparatus to form the photoelectric conversion layer 105 (photoelectric conversion layer forming step).
The CVD apparatus used at this time is a plasma CVD apparatus, which forms a film by facing the electrode for film formation so that the distance from the film formation surface of the substrate to be formed is a predetermined distance. is there. Further, this CVD apparatus can form a desired film by changing the output, changing the mixing ratio of the source gases, or adjusting the film forming temperature and the film forming time.

When the photoelectric conversion layer forming step is completed, the back electrode layer 106 is formed on the substrate on which the photoelectric conversion layer 105 is formed by a sputtering method, a vacuum evaporation method, or the like (back electrode layer forming step).
The above is the solar cell forming step.

Subsequently, the evaluation apparatus 1 is used to evaluate the solar cell 100 manufactured in the above-described solar cell formation step, and the evaluation result is fed back to the subsequent manufacturing of the solar cell 100.
In this embodiment, the prescription of the photoelectric conversion layer forming step is adjusted so that the rate limiting of the solar cell 100 is on the top cell 51 side. That is, the solar cell 100 is manufactured, the rate-limiting cell is specified and evaluated by the evaluation device 1 with respect to the manufactured solar cell 100, and the evaluation result indicates that the short-circuit current ratio Ra is larger than a predetermined reference and the short-circuit current The prescription is adjusted so that the ratio Rb is also larger than a predetermined reference.

Specifically, in the subsequent production of the solar cell 100, the predetermined range in the region IV of FIG. 4 is determined based on the evaluation result so that the top cell 51 becomes the rate-limiting and the rate-limiting rate. Any one of the following conditions (1) to (5) is changed when each element cell 51, 52, 53 is formed into a film by a CVD apparatus so as to belong to the above.
(1) Relative film thickness (2) Film forming temperature (3) Raw material gas ratio (4) Distance between in-process solar cell substrate and electrode of CVD apparatus (5) Output of CVD apparatus

  More specifically, the ratio Ra of the current value I1 when the solar cell 100 is irradiated with the first limiting light with respect to the current value Isc when the solar cell 100 is irradiated with pseudo-sunlight with a condition corresponding to STC is 73% or more. The second light ray condition for the current value Iα1 under the first light ray condition when 75% or less is applied to the light receiving surface of the solar cell 100 with the first light ray under the first light ray condition and the second light ray under the second light ray condition. The prescription is adjusted so that the ratio Rb of the current value Iα2 at 1.0 is 1.02 or more.

  As an example of this adjustment, when the short-circuit current ratio Ra is equal to or higher than the first threshold and the short-circuit current ratio Rb is also smaller than the second threshold (in the case of the region III), the film thickness of the bottom cell 53 is increased. Or by reducing the film thickness of the top cell 51 and increasing the relative film thickness of the bottom cell 53 with respect to the top cell 51, the top cell 51 is adjusted to be rate-limiting.

  In another example, when the short-circuit current ratio Rb is too large, the thickness of the top cell 51 is increased or the thickness of the middle cell 52 and the bottom cell 53 is decreased, so that the middle cell 52 and the bottom cell of the top cell 51 are reduced. By adjusting the relative film thickness with respect to 53, the top cell 51 is adjusted to a predetermined rate.

  According to the manufacturing method of the solar cell 100 of this embodiment, since the evaluation result using the evaluation apparatus 1 is used for feedback, the solar cell 100 of a certain quality or higher with which the top cell 51 has a predetermined rate is mass-produced. it can.

  Finally, the solar cell 100 recommended as an evaluation target of the evaluation device 1 of the present embodiment will be described.

  As shown in FIG. 5, the solar cell 100 is obtained by laminating a transparent electrode layer 103, a photoelectric conversion layer 105 including three element cells 51, 52, and 53, and a back electrode layer 106 on a transparent insulating substrate 102. It is.

The transparent insulating substrate 102 is a substrate having transparency and insulation, and is a support substrate that supports each layer.
The transparent insulating substrate 102 is not particularly limited as long as it has transparency and insulating properties. For example, a glass substrate or a transparent resin substrate can be used.
The transparent insulating substrate 102 may be a flexible substrate having flexibility.

The transparent electrode layer 103 is a conductive layer having transparency and conductivity.
The transparent electrode layer 103 is not particularly limited as long as it has electrical conductivity and translucency. For example, a transparent conductive metal such as indium tin oxide (ITO) or zinc oxide (ZnO ₂ ). Organic conductive materials such as oxides and graphene sheets, and conductive metal thin films such as silver, aluminum, and copper can be employed.
The transparent electrode layer 103 may have a single layer structure or a multilayer structure.

  As shown in FIG. 5, the photoelectric conversion layer 105 includes a first element cell 51, a second element cell 52, and a third element cell 53 stacked in this order from the transparent electrode layer 103 side (light incident side). Are electrically and physically connected in series. That is, the solar battery 100 is a three-junction solar battery in which three element cells 51, 52, and 53 are joined in series.

  The first element cell 51 functions as a top cell of the photoelectric conversion layer 105 and is an amorphous silicon photoelectric conversion unit.

  The first element cell 51 includes a p-type amorphous semiconductor layer 60, an i-type amorphous semiconductor layer 61, and an n-type amorphous semiconductor layer 62 from the transparent electrode layer 103 side. The film can be formed by a CVD apparatus.

The p-type amorphous semiconductor layer 60 is a layer that functions as a p-type semiconductor, for example, a p-type amorphous silicon carbide layer.
The i-type amorphous semiconductor layer 61 is a layer that functions as an i-type semiconductor (substantially intrinsic semiconductor), and is, for example, an i-type amorphous silicon layer.
The n-type amorphous semiconductor layer 62 is a layer that functions as an n-type semiconductor, for example, an n-type amorphous silicon layer.

The second element cell 52 functions as a middle cell of the photoelectric conversion layer 105 and is an amorphous germanium photoelectric conversion unit.
The second element cell 52 is a photoelectric conversion unit including an i-type amorphous silicon germanium semiconductor layer 66.
The second element cell 52 includes a p-type amorphous semiconductor layer 65, an i-type amorphous silicon germanium semiconductor layer 66, and an n-type crystalline semiconductor layer 67, and any of these layers can be formed by a CVD apparatus. It has become.

The p-type amorphous semiconductor layer 65 is a layer that functions as a p-type semiconductor, for example, a p-type amorphous silicon layer.
The i-type amorphous silicon germanium semiconductor layer 66 is a layer that functions as an i-type semiconductor, for example, an i-type amorphous silicon germanium layer.
The n-type crystalline semiconductor layer 67 is a layer that functions as an n-type semiconductor, for example, an n-type crystalline silicon layer.

The third element cell 53 functions as a bottom cell of the photoelectric conversion layer 105 and is a crystalline silicon photoelectric conversion unit.
The third element cell 53 includes a p-type crystalline semiconductor layer 70, an i-type crystalline semiconductor layer 71, and an n-type crystalline semiconductor layer 72, and any layer can be formed by a CVD apparatus. Yes.
The p-type crystalline semiconductor layer 70 is a layer that functions as a p-type semiconductor, for example, a p-type crystalline silicon layer.
The i-type crystalline semiconductor layer 71 is a layer that functions as an i-type semiconductor, for example, an i-type crystalline silicon layer.
The n-type crystalline semiconductor layer 72 is a layer that functions as an n-type semiconductor, for example, an n-type crystalline silicon layer.

The back electrode layer 106 is an electrode layer that forms a pair with the transparent electrode layer 103 and functions as an electrode.
The back electrode layer 106 is not particularly limited as long as it has conductivity. For example, metals such as aluminum, silver, gold, copper, platinum, and chromium, metal alloys, and metal composites can be used.
Note that the back electrode layer 106 may have a multilayer structure. For example, the back electrode layer 106 may have a multilayer structure of a transparent conductive oxide layer and a metal layer.

  In the above-described embodiment, the first element cell 51, the second element cell 52, and the third element cell 53 are stacked in this order as the photoelectric conversion unit, but the present invention is not limited to this, The stacking order of the first element cell 51, the second element cell 52, and the third element cell 53 is not particularly limited.

In the above-described embodiment, the short-circuit current ratio obtained by dividing the short-circuit current as an absolute amount by the short-circuit current is used for evaluation, but the present invention is not limited to this.
For example, the short-circuit current density may be evaluated by a short-circuit current density ratio obtained by dividing the short-circuit current density by the short-circuit current density, or the short-circuit current may be converted into voltage or power and evaluated by the voltage ratio or power ratio. That is, the short-circuit current ratio may be indirectly evaluated by converting to a corresponding unit at 1: 1 using other factors.

  In the above-described embodiment, the condition corresponding to the reference state is the reference of the pseudo sunlight, but the present invention is not limited to this, and the condition corresponding to the sunlight state other than the reference state is set to the pseudo sunlight. It is good also as a standard of.

  In the above description of the embodiment, the middle evaluation step and the top / bottom evaluation step are described in this order. However, the order of the middle evaluation step and the top / bottom evaluation step is not particularly limited. The top / bottom evaluation step may be performed after the middle evaluation step, or the middle evaluation step may be performed after the top / bottom evaluation step.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

  The evaluation procedure of the solar cell of the specific Example of this invention and these evaluation results are demonstrated.

Example 1
Example 1 was a three-junction solar cell, and used a solar cell that controlled the rate toward the top cell when irradiated with pseudo-sunlight using a solar simulator.

(Example 2)
Example 2 is a three-junction solar cell similar to Example 1, and is rate-controlled closer to the top cell than Example 1 when irradiated with simulated sunlight using the same solar simulator as Example 1. A solar cell that takes

(Example 3)
Example 3 is a three-junction solar cell similar to Example 1, and used a solar cell that controls the rate toward the middle cell when irradiated with simulated sunlight using the same solar simulator as in Example 1. .

Example 4
Example 4 is a three-junction solar cell similar to Example 1, and when the simulated solar light is irradiated using the same solar simulator as Example 1, any element cell is balanced. A battery was used. That is, a solar cell in which the current density of each element cell has a substantially close value was used.

As a top-bottom evaluation process, pseudo-sunlight (long wavelength light with respect to the illuminance of the mixed light 17) under conditions (air mass 1.5, 1000 W / m ² , 25 ° C.) corresponding to a reference state (STC) that is one state of sunlight 16 illuminance ratio is 0.685), and the first light beam condition in which the mixing ratio of the short wavelength light 15 and the long wavelength light 16 to the pseudo-sunlight is changed to reduce the ratio of the long wavelength light 16 to the mixed light 17 The first light beam and the second light beam under the second light beam condition in which the ratio of the long wavelength light 16 to the mixed light 17 was increased were applied to the light receiving surfaces of the solar cells of Examples 1 to 4.
Specifically, for the solar cells of Examples 1 to 4, as the first light condition, the second short wavelength condition where the illuminance ratio of the long wavelength light 16 to the illuminance of the mixed light 17 is 0.605, and the mixing It implements on the 1st short wavelength conditions that the illuminance ratio of the long wavelength light 16 with respect to the illuminance of the light 17 is 0.645, and the illuminance ratio of the long wavelength light 16 to the illuminance of the mixed light 17 is 0.725 as the second light condition. And the second long wavelength condition in which the illuminance ratio of the long wavelength light 16 to the illuminance of the mixed light 17 is 0.765.
And about the solar cell of Examples 1-4, the short circuit current value under the pseudo-sunlight of the conditions equivalent to STC, 2nd short wavelength conditions, 1st short wavelength conditions, 1st long wavelength conditions, and 2nd Short-circuit current values under long wavelength conditions were plotted against each illuminance ratio.

The result is shown in FIG.
As can be seen from FIG. 6, each of the waveforms of Examples 1 to 4 had a continuous mountain shape.
In the solar cells of Examples 1 and 2 that are top rate-limiting, the peak is shifted to the low illuminance ratio side with respect to 0.685 which is the illuminance ratio of the pseudo-sunlight under the condition corresponding to STC. In the solar cell of Example 3, the peak shifted to the high illuminance ratio side with respect to 0.685 which is the illuminance ratio of the pseudo-sunlight under the condition corresponding to STC. Moreover, in the solar cell of Example 2 which has rate-controlling on the top cell side, the peak was shifted to the low illuminance ratio side as compared with the solar cell of Example 1.
The peaks of Examples 1 and 2 in which the top cell is rate-controlled are shifted to the low illuminance ratio side compared to the peak of Example 4 in which each cell is balanced, and the peak in Example 3 in which the middle cell is rate-limiting. Was shifted to the high illuminance ratio side compared to the peak of Example 4 in which each cell was balanced.

(Example 5)
Example 5 is a three-junction solar cell, and a solar cell whose top cell is known to be rate-limiting in advance by measurement with an external engine was used.

(Example 6)
Example 6 is a three-junction solar cell similar to that of Example 5, and is a solar cell whose top cell is known to be rate-determined in advance by measurement of an external engine. Used solar cell.

(Example 7)
Example 7 is a three-junction solar cell similar to that in Example 5, and a solar cell whose middle cell is known to be rate-determined in advance by measurement of an external engine was used.

(Example 8)
Example 8 is a three-junction solar cell similar to that in Example 5, and a solar cell whose bottom cell is known to be rate-limiting in advance by measurement with an external engine was used.

  The solar cells were evaluated for the solar cells of Examples 5 to 8.

  First, as a middle evaluation step, pseudo-sunlight (the illuminance ratio of the long-wavelength light 16 to the illuminance of the mixed light 17 is 0.685) under the conditions corresponding to STC is applied to the light receiving surfaces of the solar cells of Examples 5-8. Irradiation and current-voltage characteristics were measured. Subsequently, the limiting filter 6 having a transmittance of about 75% at the wavelength λ1, a transmittance of about 55% at the wavelength λ2, and a transmittance of about 80% at the wavelength λ3 is used, and the first limiting light of the first limiting condition is used. Was irradiated to the light receiving surface of the solar cell, and the current-voltage characteristics were measured.

Next, as a top-bottom evaluation process, in the same manner as described above, the mixing ratio of the short wavelength light 15 and the long wavelength light 16 is changed with reference to the pseudo sunlight corresponding to the STC, and the long wavelength light with respect to the mixed light 17 is changed. The first light beam under the first light beam condition with the ratio of 16 reduced and the second light beam with the second light beam condition with the increased ratio of the long wavelength light 16 to the mixed light 17 are applied to the light receiving surface of the solar cells of Examples 5-8. Irradiated.
Specifically, as the first light ray condition, the second short wavelength condition where the illuminance ratio of the long wavelength light 16 to the illuminance of the mixed light 17 is 0.605, and the illuminance ratio of the long wavelength light 16 to the illuminance of the mixed light 17. The first short wavelength condition is 0.645, and the second light ray condition is a first long wavelength condition where the illuminance ratio of the long wavelength light 16 to the illuminance of the mixed light 17 is 0.725, and the mixed light 17 It implemented on 2nd long wavelength conditions from which the illuminance ratio of the long wavelength light 16 with respect to illuminance of 0.765 becomes 0.765.
The spectral waveforms of Examples 5 to 8 all had a continuous mountain shape.

  As a comprehensive evaluation process, for Examples 5 to 8, the ratio Ra of the short-circuit current value I1 under the first limiting condition to the short-circuit current value Isc under the condition corresponding to STC, and the short-circuit current under the first short wavelength condition The ratio Rb of the short circuit current value under the first long wavelength condition to the value was calculated, and the short circuit current ratio Rb to the short circuit current ratio Ra was plotted.

The result is shown in FIG. As can be seen from FIG. 7, in the solar cells of Examples 5 and 6 that are top rate-limiting, the short-circuit current ratio Ra exceeded 0.7 and the short-circuit current ratio Rb exceeded 1 and belonged to the region IV. From this, it was possible to identify that the solar cells of Examples 5 and 6 were top rate-limiting.
In the solar cell of Example 7 which is middle rate limiting, the short circuit current ratio Ra was less than 0.7, the short circuit current ratio Rb was more than 1, and belonged to the region II. From this, it has been identified that the solar cell of Example 7 has a rate-determining rate on the top side even in the middle rate-limiting.
In the solar cell of Example 8 which is bottom-controlling, the short-circuit current ratio Ra exceeded 0.7, and the short-circuit current ratio Rb fell below 1, and belonged to the region III. From this, it was able to identify that the solar cell of Example 8 was bottom rate-limiting.

  From the above, in any of Examples 5 to 8, the rate-limiting cell and the rate-limiting rate could be accurately evaluated.

Example 9
In Example 9, a solar cell produced with a reference formulation serving as a reference was used.

(Example 10)
In Example 10, compared with Example 9, a solar cell manufactured using a formulation in which the thickness of the top cell was reduced and the raw material gas ratio of the middle cell was changed was used.

(Example 11)
Example 11 used the solar cell produced by the prescription | regulation which made the film thickness of a top cell thick with respect to Example 9, and also changed the raw material gas ratio of a middle cell.

(Example 12)
Example 12 used a solar cell produced by changing the raw material gas ratio of the middle cell with respect to Example 9.

  In the same manner as described above, solar cells were evaluated for Examples 9 to 12, and the ratio Ra of the short-circuit current value I1 under the first limiting condition to the short-circuit current value Isc under the condition corresponding to STC, and the first short The ratio Rb of the short-circuit current value under the first long wavelength condition to the short-circuit current value under the wavelength condition was calculated, and the short-circuit current ratio Rb with respect to the short-circuit current ratio Ra was plotted.

  As shown in FIG. 8, in each of Examples 9 to 12, the plots were plotted at substantially the same positions, and the rate-limiting cells could be identified.

1 Evaluation Device 2 Light Source Device (Light Irradiation Device)
6 Restriction filter 11 Short wavelength light source 12 Long wavelength light source 15 Short wavelength light 16 Long wavelength light 17 Mixed light 51 Top cell (first element cell)
52 Middle cell (second element cell)
53 Bottom cell (third element cell)
100 Solar cell I1, Isc, Iα1, Iα2 Short circuit current Ra Short circuit current ratio Rb Short circuit current ratio

Claims (9)

A solar cell evaluation device in which a first element cell, a second element cell, and a third element cell are connected in series,
The maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the first element cell is shorter than the maximum absorption wavelength of the second element cell, and the maximum corresponding to the maximum value of the relative spectral sensitivity of the third element cell. In the solar cell evaluation apparatus in which the absorption wavelength is longer than the maximum absorption wavelength of the second element cell,
Having a light irradiation device,
The light irradiation device can irradiate pseudo-sunlight under a condition corresponding to one state of sunlight, and has a predetermined ratio of irradiance at the maximum absorption wavelength of the second element cell with respect to the pseudo-sunlight. Can be irradiated with the first limiting light that is preferentially limited by
When evaluating the solar cell, the short-circuit current value when the solar cell is irradiated with the pseudo-sunlight and the short-circuit current value when the solar cell is irradiated with the first limiting light are directly or indirectly determined. An evaluation apparatus for a solar cell, wherein   2. The solar cell evaluation apparatus according to claim 1, wherein the irradiance of the first limiting light is 60% or less of the irradiance of pseudo-sunlight at the maximum absorption wavelength of the second element cell. The maximum absorption wavelength of the second element cell is in a wavelength region of 550 nm to 750 nm,
Having a limiting filter for limiting the irradiance to the pseudo-sunlight,
3. The solar cell evaluation apparatus according to claim 1, wherein the limiting filter has a total transmittance of 60% or less within a range of 50 nm from a maximum absorption wavelength of the second element cell. 4. The light irradiation device can independently irradiate short wavelength light having a peak on the short wavelength side with an irradiance of 650 nm or less and long wavelength light having a peak on the long wavelength side with an irradiance of more than 650 nm, The pseudo-sunlight can be irradiated by a mixed light of the short wavelength light and the long wavelength light,
The light irradiation device can implement a first light beam condition for irradiating a first light beam and a second light beam condition for irradiating a second light beam,
The first light beam has a ratio α1 of long wavelength light to mixed light that is smaller than a ratio α3 of long wavelength light to mixed light in a condition corresponding to one state of the sunlight,
The second light beam has a ratio α2 of long-wavelength light to mixed light that is greater than a ratio α3 of long-wavelength light to mixed light in a condition corresponding to one state of sunlight,
The solar cell is irradiated with the first light beam and the second light beam according to the first light beam condition and the second light beam condition, and a current value under the first light beam condition and a current value under the second light beam condition are directly measured. The solar cell evaluation apparatus according to any one of claims 1 to 3, wherein the solar cell is evaluated by comparison with the target or indirectly.   The difference between the ratio α1 of the long wavelength light to the mixed light under the first light condition and the ratio α3 of the long wavelength light to the mixed light under the condition corresponding to one state of the sunlight is 5. The solar cell evaluation apparatus according to claim 4, wherein the solar cell evaluation device is substantially equal to a difference between a long-wavelength light ratio α <b> 2 and a long-wavelength light ratio α <b> 3 to mixed light under a condition corresponding to one state of the sunlight. The first light beam has a ratio α1 of long wavelength light to mixed light that is 0.96 or more of a ratio α3 of long wavelength light to mixed light in a condition corresponding to one state of sunlight,
The ratio α2 of the long wavelength light to the mixed light is 1.04 or less of the ratio α3 of the long wavelength light to the mixed light under the condition corresponding to one state of the sunlight. Item 6. The solar cell evaluation apparatus according to Item 4 or 5. A solar cell evaluation device in which a first element cell, a second element cell, and a third element cell are connected in series,
The maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the first element cell is shorter than the maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the second element cell. In the solar cell evaluation apparatus, the maximum absorption wavelength corresponding to the maximum value of the spectral sensitivity is longer than the maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the second element cell.
Having a light irradiation device,
The light irradiation device can independently irradiate short wavelength light having a peak on the short wavelength side with an irradiance of 650 nm or less and long wavelength light having a peak on the long wavelength side with an irradiance of more than 650 nm, The light receiving surface of the solar cell can be irradiated with mixed light of the short wavelength light and the long wavelength light,
The light irradiation device can irradiate pseudo-sunlight with a condition corresponding to one state of sunlight by the mixed light,
The light irradiation device can implement a first light beam condition for irradiating a first light beam and a second light beam condition for irradiating a second light beam,
The first light beam has a ratio α1 of long wavelength light to mixed light that is smaller than a ratio α3 of long wavelength light to mixed light in a condition corresponding to one state of the sunlight,
The second light beam has a ratio α2 of long-wavelength light to mixed light that is greater than a ratio α3 of long-wavelength light to mixed light in a condition corresponding to one state of sunlight,
The solar cell is irradiated with the first light beam and the second light beam according to the first light beam condition and the second light beam condition, and a current value under the first light beam condition and a current value under the second light beam condition are directly measured. A solar cell evaluation apparatus, wherein the solar cell is evaluated by comparison with the target or indirectly. A method of manufacturing a solar cell in which a first element cell, a second element cell, and a third element cell are connected in series,
The maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the first element cell is shorter than the maximum absorption wavelength of the second element cell, and the maximum corresponding to the maximum value of the relative spectral sensitivity of the third element cell. A method for producing a solar cell in which the absorption wavelength is longer than the maximum absorption wavelength of the second element cell,
It evaluates using the evaluation apparatus in any one of Claims 1-6, and the said 1st limiting light with respect to a short circuit current value when the said solar cell is irradiated to the said solar cell is irradiated to the light-receiving surface of the said solar cell A method for manufacturing a solar cell, comprising adjusting the prescription so that the ratio of the short-circuit current value when the resistance is 73% to 75%. A method of manufacturing a solar cell in which a first element cell, a second element cell, and a third element cell are connected in series,
The maximum absorption wavelength corresponding to the maximum value of the relative spectral sensitivity of the first element cell is shorter than the maximum absorption wavelength of the second element cell, and the maximum corresponding to the maximum value of the relative spectral sensitivity of the third element cell. A method for producing a solar cell in which the absorption wavelength is longer than the maximum absorption wavelength of the second element cell,
It evaluates using the evaluation apparatus in any one of Claims 4-6, The electric current when the said 1st limiting light with respect to the electric current value when the said solar cell is irradiated to the said solar cell is irradiated to the said solar cell The ratio of the values is 73% or more and 75% or less, and the first light condition and the second light condition in the second light condition when the solar cell is irradiated with the first light and the second light. A method for manufacturing a solar cell, comprising adjusting the prescription so that a ratio of a current value under the first light beam condition to a current value is 1.02 or more.

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