PEM FUEL CELLS

Powering the electrified future

The proton-exchange membrane (PEM) fuel cell is an electrochemical cell that uses hydrogen chemical energy to produce electricity. A PEM fuel cell system can operate at low temperatures, enabling fast start-up and shut-down, making it ideal for mobility applications. It is commonly used to power electric engines in fuel cell electric vehicles (FCEVs) – buses, trucks, and cars, but also trains, forklifts, ships, and even airplanes. When hydrogen acts as the fuel, the only products of the process are electricity, water, and heat.

A single PEM fuel cell consists of a set of components in a chemical electrolyte, which generates a small amount of power. To generate power for different needs, a few up to several hundred fuel cells are stacked, creating the core of a PEM fuel cell system. Between every cell in the stack are separator plates, also known as bipolar plates, which are key to the performance of the PEM fuel cell system.

For increased stack performance and lifespan, metal bipolar plates in PEM fuel cells need protection with high-performance, conductive, and corrosion-resistant coatings. Uncoated metal plates corrode and release metal ions into the stack. These ions can irreversibly damage the fuel cell stack membrane, reducing power output. Loss of conductivity and corrosion significantly shorten fuel cell lifetime and must be prevented. According to the US Department of Energy, PEM fuel cell systems have target lifetimes of at least 30,000 hours for heavy-duty applications and 8,000 hours for mid-range applications.

In heavy-duty mobility applications, to mitigate hydrogen starvation and maintain optimal performance throughout the lifetime of vehicle, the bipolar plate coating must withstand extreme potential spikes and temperatures without degradation.

Why PVD technology for fuel cells

• Corrosion Resistance: PVD coatings provide excellent protection against corrosion, which is crucial for the longevity and efficiency of fuel cells.
• Improved Conductivity: The coatings enhance the electrical conductivity of bipolar plates and interconnects, which is essential for efficient energy transfer within the fuel cell.
• Durability: PVD coatings are highly durable and can withstand the harsh operating conditions of fuel cells, including high temperatures and chemical exposure.
• Cost-Effectiveness: PVD technology can reduce material costs by enabling less expensive base materials while achieving high performance.
• Environmental Benefits: PVD processes are generally more environmentally friendly compared to other coating methods, as they produce fewer hazardous by-products.