Notable cell voltages are considered early indicators of degradation, local overload, or cell reversal, meaning a reversal of cell polarity. They can also indicate hotspots as well as membrane or contact issues. Operators should be able to recognize critical trends in the operation of fuel cell or electrolyser stacks earlier and respond accordingly, for example by reducing the load or specifically shutting down an affected stack. In the end, this can extend the lifespan of the stacks.
Monitor strong stacks up to 1,500 volts with a common station
The new module from Weidmüller measures the voltage difference between two consecutive channels. This way, it captures the voltage of individual cells or cell groups. With the 16 connections, up to 15 individual cell voltages per module can be monitored on 15 differential analog inputs—and all on 11.5 millimeters of width. According to the manufacturer, an integrated switchable bridge is intended to simplify the series connection of multiple modules. Double terminal assignment should thus be eliminated. A fieldbus coupler supports up to 64 active I/O modules.
Measuring ranges from 0 to 3 volts, 0 to 30 volts, and -100 to 100 volts are configurable. For PEM electrolysis, Weidmüller specifies typical cell voltages of 1.7 to 2.2 volts per cell, so that with 1,500 volts of isolation strength, up to 880 cells can ideally be monitored in a single u-remote station.
The system is modular. Electronic modules can be replaced or added without dismantling the entire station.
An integrated web server supports parameterization, diagnostics, as well as loading and saving configurations. The system can be connected to existing automation via PROFINET, EtherCAT, Modbus TCP, and EtherNet/IP.
According to the company, cloud and edge integration is also possible via the u-mation platform. This is intended to support condition-based maintenance, meaning maintenance based on measurement data instead of fixed intervals.
The new module is certified according to CE, ATEX, IECEx, UL, and DNV, among others, for use in explosive areas of ATEX Zone 2.
What else is happening in cell voltage monitoring? Read our overview article in H2international 3/2026 with a free trial subscription.
