Virtually all fuel cell vehicles are electric vehicles with an on-board power generation resource (the fuel cell). As electric vehicles, they need to meet specific standards for high-voltage equipment. To ensure that equipment operates within defined safety parameters, a minimum insulation resistance of electrically conductive components to the equipment’s ground must be maintained.
With PEM technology fuel cells, a liquid coolant system is used to maintain desired operating temperatures. Through coolant circulation, the bipolar plates of the fuel cell stack may be electronically linked to grounded neighboring components. Solubility of ionic components in the coolant circuit of fuel cell stacks may create a problem by increasing conductivity, which can cause electrical short-circuit effects and power loss – and may even lead to system shutdown.
Over the life of a fuel cell, ions can penetrate the coolant circuit from a variety of sources. They can come from the fuel cell itself (ion leaching), can be created by the coolant (often water-glycol mixtures) interacting with various cooling system materials and by the aging/decomposition of the coolant.
The Hengst Blue.iox ion exchanger ensures a rapid reduction of ion concentration within the coolant circuit. It can either be integrated into the main coolant flow or in a parallel/bypass flow to the coolant circuit (see diagram 1). The ion exchanger is available in capacities up to 1500 meq. and can be configured for use in a wide range of fuel cell applications.
This illustration demonstrates how insulation resistance from adjacent grounded components can be achieved using a parallel/bypass flow.

The innovative design of the resin system in the Blue.iox filter cartridge ensures effective ion reduction throughout the entire service interval. All materials used are designed to be long-lasting and were selected for their compatibility with typical coolant formulations.
In addition, the Hengst Blue.iox ion exchanger is designed to be efficient and easy to service. The screw cap allows the filter cartridge to be changed cleanly using standard tools, while the integrated shut-off valves ensure that no coolant leaks out during servicing.
Hengst offers analysis and mobile measurements to determine the optimal ion resin design. Please feel free to contact us!
Mathias Diekjakobs
Product Manager
Fuel Cell Filtration & Fluidmanagement
m.diekjakobs[at]hengst.de