Battery felts and bipolar plates for redox flow batteries

SIGRACELL® carbon and graphite felts

Redox flow batteries enable energy storage on a scale of kWh to MWh and provide the perfect solution for stationary applications. They are well-suited as temporary storage for grid stabilization, industrial back-up power, integration of renewables such as wind and photovoltaic as well as off-grid power supply for mobile radio transmitters and remote households. The main advantage of redox flow batteries is that they separate output (MW) and energy (MWh). The two can be adjusted independently of one another and are easily adaptable to the specific requirements at hand.

SGL Group ranks among the leading manufacturers of specialty graphites and graphite components for redox flow batteries.

We have applied our long-term experience and close cooperation with customers to develop special materials and products for energy storage: SIGRACELL battery felts and bipolar plates made of expanded graphite. Continuous improvement of our materials has significantly enhanced the performance and service life of our customers flow batteries.

Low cell resistivity and high electrolyte permeability are crucial factors for flow battery electrodes. Accordingly, the contact resistivity of the bipolar plate and felt electrode, as well as the permeability of the felt electrode largely depend on surface pressure and felt compression, and can be controlled by the compression rate: As the compression rate increases, resistivity decreases, as does permeability and vice versa.

Inhomogeneity in the battery felt can lead to impermeable areas reducing the overall performance of the system. Therefore, SGL Group is continuously working on tighter tolerances for area weight and thickness of our battery felts. This enables our customers to optimize the compression rates to ensure the best battery performance possible.

Application-specific specialty graphites for redox flow batteries

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