I-V Measurement Systems

 
System DetailsStandard Software FeaturesAdvanced Software Features

The Solar Cell I-V Curve Data Acquisition System characterizes the current-voltage (I-V) characteristics of photovoltaic devices with currents up to 20.0 amperes. It calculates the solar cell parameters, generates printable test reports and saves test data in text files. IV Curves are measured using classic four probes (Kelvin) technique. The system includes electronics, software, rack-mount computer, chuck and cell testing fixture with irradiance monitoring and optional temperature control. It interfaces with the customers’ Solar Simulator or a Solar Simulator can be supplied.

SYSTEM DETAILS

Test Fixture for Solar Simulators with area of illumination ≤ 100mm x 100mm

The I-V Curve Data Acquisition includes a fixture for holding cells for testing (see Figure 1 below). This fixture can accommodate cells from small to up to 100 mm x 100 mm. Adjustable cell stops, in the X & Y-axis, are provided to consistently locate the cells for testing. Two micro-manipulators are provided as shown in Figure 1. Each micro-manipulator has two spring loaded contacts to allow 4-wire measurement even for cells that have top contacts only. Two back-side voltage contacts are embedded in the Plate (galvanically isolated from the Plate) and make good electrical contact when the cell is held down by vacuum to the plate. All voltage and current probes are gold-plated. The cell is held down with vacuum during testing (built-in vacuum pump).

With optional Temperature Control, the cell holding plate can be either cooled or heated in the temperature range of 5-60° C using Peltier cells. Temperature of the plate is measured automatically with accuracy of <±0.5° C and is monitored during cell measurement.


View of a typical cell measuring table with bottom current & voltage contacts and two (2) micro-manipulators for top cell contacts. Each Micro-Manipulator has one current & one voltage contact.
View of a typical cell measuring table with bottom current & voltage contacts and two (2) micro-manipulators for top cell contacts. Each Micro-Manipulator has one current & one voltage contact.


Test Fixture for Solar Simulators with area of illumination ≥ 100mm x 100mm

The I-V Curve Data Acquisition includes a fixture for holding test devices (See Figure 2 below). This fixture can accommodate cells from small to up to 300 mm x 300 mm. Adjustable cell stops, in the X & Y-axis, are provided to consistently locate the cells for testing. For top cell contacting, two bus bars with multiple spring loaded contacting probes (20 per bus bar) are mounted on a frame. The frame can be manually raised to place the cell on the plate for testing. The cell is held down with vacuum (built-in) during testing. After placing the cell in position, the frame can be manually lowered to make probe contact with the cell. Once in the down position, the frame is held down by clasps to maintain contact with the cell. Optional third bus bar and automatic cell contacting is available upon request.

Two back-side voltage contacts are embedded in the platen (galvanically isolated from the platen) and make good electrical contact when the cell is held down by vacuum to the platen. All of the voltage and current probes are gold-plated. Alternative cell contacting mechanisms are available upon request.

With the optional Temperature Control, Cell Holding Plate can be either cooled or heated in the temperature range of 5-60° C using Peltier cells. Temperature of the platen is measured automatically with accuracy of <±0.5° C and is monitored during cell measurement.


View of a typical cell measuring table with bottom current & voltage contacts and two (2) micro-manipulators for top cell contacts. Each Micro-Manipulator has one current & one voltage contact.
View of a typical cell measuring table with bottom current & voltage contacts and two (2) micro-manipulators for top cell contacts. Each Micro-Manipulator has one current & one voltage contact.


Options for Both Types of Systems

Temperature Control
Temperature control of the Cell Holding Plate is available. The standard temperature control range is 5-60°C. Other temperature control ranges are available. Temperature control accuracy is <±1°C.

Setup and Training
System setup is easy when using the instructions provided in the manual. If desired, PET will provide system setup and training at the customer’s facility.


The above specifications provide general information about this product. Actual product can be customized to meet the needs of individual customers.

Typical I-V System Console - ≤ 5A Current
Typical I-V System Console - ≤ 5A Current
    Typical I-V System Console – 15A/20A Current
Typical I-V System Console – 15A/20A Current


The IV Systems come with a choice of two different types of IV Measurement Software: Standard Software & Advance Software. The configuration of Console depends on the maximum current measurement capability.

STANDARD SOFTWARE FEATURES

  • MS Windows environment and user friendly software.
  • Computes solar cell parameters including ISC, VOC, VMAX, IMAX, PMAX, FF, Efficiency, RS, RSH, JSC, RS Density, RSH Density.
  • Measures Light & Dark IV Curves.
  • Scan data can be saved manually or automatically.
  • In automatic file save mode, the user defines a file name series. In this mode, the software creates a summary file of all the major measured parameters for all the cells tested in that series. This helps in analyzing the data for a series of cells tested for trends etc.
  • Provides printable test reports and test data in text files for easy exchange between programs.
  • Solar Simulator shutter control (Solar Simulator sold separately).

Cell Parameter Scan Screen
Cell Parameter Scan Screen
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Scanning and File Options Screen
Scanning and File Options Screen
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Source Meter Information Screen
Source Meter Information Screen
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MODEL

CC-1 CC-3 CC-5 CC-20
Max. Current Range (A) ±1 ±3 ±5 ±20
Keithley Source Meter Model # 2400 2420 2440 2651
Available Current Ranges ±1A, ±100mA, ±10mA, ±1mA, ±100µA, 10µA, ±1µA ±3A, ±1A, ±100mA, ±10mA, ±1mA, ±100µA, 10µA ±5A, ±1A, ±100mA, ±10mA, ±1mA, ±100µA, 10µA ±20A, ±10A, ±5A, ±1A, ±100mA, ±10mA, ±1mA, ±100µA, ±10µA, ±1µA, ±100nA
Max. Voltage Range (V) ±20 ±60 ±40 ±40
Available Voltage Ranges ±20V, ±2V, ±200mV ±60v, ±20V, ±2V, ±200mV ±40V, ±10V, ±2V, ±200mV ±40V, ±20V, ±10V, ±1V, ±100mV
Max. Power (W) 20 60 50 200
Measurement Resolution 16 Bit
Measurement Accuracy Better than 0.5%
Measurement Mode Fixed or Auto
Measurement Time (Light) < 500ms for stable light (Up to 4s if filtering for light fluctuations required)
Measurement Time (Dark) 100-1,000ms
Maximum Points per Curve 275
Maximum Data Acquisition Speed 100kHz
Maximum Cell Throughput 1,200/Hour (With optional Robotics)
Phase (Power) Single Phase
Voltage (Volts)/Frequency (Hz) 115/220VAC: 50-60Hz
Max. Power Consumption (W) 40 W (Up to 600W With Peltier Cells)


ADVANCE SOFTWARE FEATURES

  • Easy to use MS Windows environment and user friendly software.
  • Software handles measurement of both P type and N type cells without any cell connection changes.
  • Advanced noise filtering feature to enable measurement of good quality I-V curves even under fluctuating intensity conditions.
  • Light Intensity & Temperature monitoring and control, 5-60°C Standard. Other ranges optional.
  • Calculation of cell series resistance according to IEC 60891 standard and ASTM E948-09 Annex A1.
  • Procedures for fitting of measured I-V Curve to either equivalent diode models, i.e. SEM-Single Exponential, DEM-Double Exponential and VDEM-Variable Double Exponential with seventeen (17) weight functions.
  • Procedures for curve correction to Standard Test Conditions (STC) to IEC 60891, Anderson’s and Blaessar’s or user defined conditions. User has the ability to perform automatic correction of measured I-V curve to STC (Standard Test Conditions), i.e. light intensity and temperature or other conditions specified by the user.
  • Computes solar cell parameters including ISC, VOC, FF, IMAX, VMAX, PMAX, Eff, Rs and Rsh and saves them automatically on hard disk drive. In addition cell’s temperature and irradiance level is measured and stored for future analysis.
  • Calculate Thermal Coefficients of ISC (α), Voc (β) & PM (γ).
  • Dark saturation current, RS and RSH determination.
  • Provides printable test reports and test data in text files for easy exchange between programs.
  • Software features include cell sorting in various categories. This cell sorting can be performed in production or in virtual binning modes specified by the user.
  • Solar Simulator shutter control. (Solar Simulator sold separately)

Majority of the features highlighted in yellow are usually not found in competitors' software.

Example of “light” measurement – Advance Software
Example of “light” measurement – Advance Software
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Example of “dark” measurement – Advance Software
Example of “dark” measurement – Advance Software
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Example of cell’s series resistance determination according to IEC 60891 & ASTM E948-09 Annex A1 Standard
Example of cell’s series resistance determination according to IEC 60891 & ASTM E948-09 Annex A1 Standard
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Example of cell’s I-V curve fitting to Double Diode equivalent electrical model
Example of cell’s I-V curve fitting to Double Diode equivalent electrical model
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MODEL

CC-1 CC-3 CC-5 CC-15 CC-20
Max. Current Range (A) ±1 ±3 ±5 ±15 ±20
Available Current Ranges ±1A, ±100mA, ±10mA, ±1mA, ±100µA, 10µA, ±1µA ±3A, ±1A, ±100mA, ±10mA, ±1mA, ±100µA, 10µA ±5A, ±1A, ±100mA, ±10mA, ±1mA, ±100µA, 10µA ±15A, ±10A, ±1A, ±100mA, ±10mA, ±1mA, ±100µA ±20A, ±10A, ±1A, ±100mA, ±10mA, ±1mA, ±100µA
Max. Voltage Range (V) ±20 ±60 ±40 ±10 ±10
Available Voltage Ranges ±20V, ±2V, ±200mV ±60v, ±20V, ±2V, ±200mV ±60V, ±20V, ±2V, ±200mV ±10V, ±5V, ±2.5V ±1.25V, ±800mV, ±400mV, ±200mV ±10V, ±5V, ±2.5V ±1.25V, ±800mV, ±400mV, ±200mV
Max. Power (W) 20 60 50 150 200
Measurement Resolution 16 Bit
Measurement Accuracy Better than 0.5%
Measurement Mode Fixed or Auto
Measurement Time (Light) < 500ms for stable light (Up to 4s if filtering for light fluctuations required)
Measurement Time (Dark) 100-1,000ms
Maximum Points per Curve 100-1,000 (model specific)
Maximum Data Acquisition Speed 100kHz 4,096
Maximum Cell Throughput 1,200/Hour (With optional Robotics)
Phase (Power) Single Phase
Voltage (Volts)/Frequency (Hz) 220VAC (115VAC Optional) / 50-60Hz
Max. Power Consumption (W) 40 W (Up to 600W With Peltier Cells)
Curve Correction to STC IEC 60891, Anderson or Blaessar
Advance Fitting of I-V Curves SEM, DEM and VDEM Models (17 Different Weight Functions)
Thermal Coefficients of Voc and Pm Standard on All Systems (With Optional Temperature Control)
Irradiance Monitoring & Correction Standard on All Systems