DiLiCo current density for baltic qFc - Lifetime analysis on the membrane

Optimized for the baltic quickCONNECTfixture. Available in three different variants.

Application

Measure current density and temperature distribution within the cell over the active cell area. With the baltic quickCONNECTfixture from the company balticFuelCells GmbH.

  • Analysis of bipolar plates (flow field design), membrane electrode assemblies (MEA) and grouting concepts
  • Evaluation of operating strategies and aging effects.
  • Life cycle test on fuel cells, electrolyzers and redox flow batteries
  • Can be combined with electronic impedance spectroscopy (1D model to 2D model)

Technical data

Current density: Up to ± 6 A
Temperature: Up to 175 °C
Number of segments: Depending on version
Cell voltage measurement: 0 to 2.5 V
Communication: CAN, USB (via Adapter)
Connections: Up to 5 temperature sensors

DiLiCo engineering at the Hannover Messe 2022

Visit DiLiCo engineering at the Hannover Messe 2022. Talk with us about the latest devlopments in the area of DiLiCco current density.
Get in contact with us personally and arrange a meeting directly at the Hannover Messe.

A selection of our customers who already use the DiLiCo current density measurement technology:

Specifications

The DiLiCo current density product series offers a completely new price level for current density, temperature and cell voltage measurement for the baltic quickCONNECT fixture FC25/100 and FC50/125 thanks to a new, proprietary measurement method. The three variants of the measurement system offer optimal prerequisites for use in various applications. Whether high current densities (DiLiCo CUSTOM) or high temperatures (DiLiCo HIGH TEMP), DiLiCo offers the right measurement system for both measurement conditions. The third variant (DiLiCo CURR TEMP) offers the possibility to determine both current density and temperature distributions inexpensively and precisely. All meters in this product line feature additionally an integrated cell voltage measurement. Optional up to five temperature sensors for the media circuits can be connected for each variant of the measuring system.

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DiLiCo current density consists of a segmented sensor layer consisting of current and temperature sensors, electronics for evaluating and transmitting the measured data to the customer's computer, and optionally, software for visualization and extensive evaluation of the measured values for current density (current strength related to area) and temperature. The segmented sensor layer is integrated between two cells, without direct contact to the gases and liquids. Each segment measures the current and temperature for a portion of the active area of the membrane electrode assembly. The area of all segments is equal to the area of the active reaction surface of the membrane.

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As a result, DiLiCo current density reveals a two-dimensional image of the distribution of current density and temperature over the area of the membrane-electrode unit. The activity of the membrane, the design of bipolar plates, seals, and other components can thus be evaluated both in operation but also out of operation. During operation, conditions such as gas undersupply, thermal hot spots, and flooding can be identified, directly measure and visualize the correlations between humidification systems and cell performance, and measure the effects of one-dimensional imprinting of AC components by electrochemical impedance spectroscopy on two-dimensional measurement by DiLiCo current density closer to the active area of the cell.

Delivery

  • DiLiCo current density sensorlayer
  • Evaluation electric with software
  • External power supply
  • Instructions

User

  • User of the baltic quickCONNECT fixture FC25/100 and FC50/125

What is meant by current density?

Galvanic cells or electrochemical energy converters, such as batteries and fuel cells, generate charge carriers inside at the electrodes. These charge carriers move and an electric current flows to the conductor (cable), which is used to supply electrical loads.

But as the operating time increases, this current continues to decrease because aging occurs at the electrodes and electrolytes. Instead of providing electrical energy, thermal losses increase and increase the heating of the cell.

The current density is defined as current per area (cross-sectional area for current). The unit is given as amps per square centimeter (A/cm²). The background is the comparability of powerful fuel cells or electrolyzers with several 100 amperes per system and smaller cells with a few amperes.

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What does current density mean for the operation of electrochemical energy converters?

The current density is a measure of the performance of galvanic cells, especially the electrodes on fuel cells, electrolyzers and redox flow batteries. The higher the value, the more electrical power the cell can provide. For the further development of galvanic cells, the values of current density and cell voltage, the two essential electrical parameters for evaluating the condition of galvanic cells, are important during operation.

In electrical engineering, the two values also form the basis of electrical engineering model descriptions of galvanic cells. For research and development, the spatially resolved current density measurement with its many current sensors distributed over the electrode area provides not only one current density value, but when viewed in the area (x,y orientation), many current density values, so that every area of the cell area can be analyzed.

Why it makes sense to measure current densities in fuel cells?

  • Identification of partial undersupply over the membrane surface, which can not be recognized by the cell voltage.
  • Recognition of local aging breakthroughs in certain membrane areas.
  • To compare different material and design configurations.
  • Evaluation of the contact resistance of bipolar plate, gas diffusion layer, seal and membrane-electrode unit for different contact pressures of the stack.
  • Statements on the quality of the gas distribution of flow fields.
  • Optimization of operating parameters by evaluation and adaptation of cell components.
  • Identification of flooding and drying conditions.
  • Data usage for modeling and extension.

What additional insights can the measurement of the current density provide?

Example: Successive flooding of the fuel cell within 60 seconds at a constant current after reducing the speed of the H2 recirculation pump.


The current density of the membrane areas at the media inlet increase by the value that the current density in the direction of the media outlet drops along the flow channel during the flooding. The membrane in the entrance area now makes up to 600 mA / cm² (previously 470 mA / cm²) compared to about 380 mA / cm² at the output (previously 520 mA / cm²). A connection between the speed of the recirculation pump and the changed humidity conditions in the output areas of the flow fields could be deduced.

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