What materials are used to make fuel cells?

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Fuel cells are becoming an increasingly popular alternative to combustion engines for clean power generation that countries and industries focus on prioritizing reductionreduction of greenhouse gas emissions as fossil fuel markets remain volatile.

The global fuel cell market was valued at nearly $4 billion in 2020, and current research predicts it could reach $32 billion by 2030. Transportation and energy sectors are expected to generate a significant percentage growth, as they were both early adopters of fuel. cells. This includes major automakers such as Toyota and Hyundai, which make fuel cell cars. Others, like GM, are investing in fuel cell solutions capable of recharging fully electric vehicles.

Image Credit: Ulbrich Stainless Steels and Specialty Metals, Inc.

Compared to traditional thermal power, the benefits of fuel cell vehicles include improvements in efficiency, no pollutant or greenhouse gas emissions, and improved range over all-electric vehicles. .

In the electricity sector, fuel cells provide energy for commercial, industrial and residential buildings, as well as long-term energy storage for the grid in reversible systems.

As there is a growing demand for this innovative technology, the demand for advanced materials to enable fuel cells to achieve peak performance will also increase.

What are fuel cells?

Fuel cells are electrochemical cells that generate electricity using only a chemical fuel and an oxidizing agent. Fuel cells that use hydrogen as a chemical fuel are completely carbon-free – their only by-products are electricity, heat and water.

Fuel cells can vary greatly in size and technologies applied depending on the end application. Some fuel cells are smaller, similar to conventional battery types and used to power forklifts. Others are large towers that could replace existing power sources and potentially generate electricity (or backup power generation) for an entire facility.

How do fuel cells generate electricity?

A fuel cell is mainly composed of two bipolar plates (anode and cathode) separated by a catalyst and an electrolyte.

In a hydrogen fuel cell, hydrogen gas flows into the negatively charged anode plate, while oxygen fills the positively charged cathode plate.

The hydrogen in the anode and the oxygen in the cathode want to react and form water, but the hydrogen cannot pass to the oxygen side of the fuel cell because of the electrolyte. Electrolytic materials only allow positively charged ions to pass (hydrogen atoms are neutral with one proton and one electron).

However, a catalyst separates the hydrogen atoms, separating the electrons from the protons. This allows protons to pass through the electrolyte, leaving electrons behind.

To allow electrons to access protons and form water, a wire is connected to help electrons pass through and react. As electrons pass through the wire, water is produced which then flows out of the system.

Electricity simply moves electrons, so electric current flowing through this wire can power vehicles, facilities, or even satellites.

Fuel cells will always have the ability to generate electricity as long as there is an available supply of fuel (in this case, hydrogen) and oxygen.

What materials are used to make fuel cells?

Fuel cell technologies can vary widely depending on the application and the power output needed. A general guideline is that the greater the power required, the larger the fuel cell should be.

This article focuses on polymer electrolyte membrane (PEM) fuel cells, a type of fuel cell commonly used to power vehicles.

What materials are used to make fuel cells?

Image Credit: Ulbrich Stainless Steels and Specialty Metals, Inc.

The two main components of a PEM fuel cell are the membrane electrode assembly (MEA) and the hardware that surrounds it.

The MEA includes the electrolyte membrane, catalyst layers, and gas diffusion layers, where chemical reactions take place to generate electricity.

Materials commonly found in MEA include polymers, ionomers, platinum powder (as a catalyst), and coated carbon paper (to diffuse gas and prevent rapid water buildup).

The hardware surrounding the MEA includes the bipolar plates and gaskets. Each individual MEA produces no more than 1V, so typically they are stacked to achieve the required voltage, with each cell divided by bipolar plates and gaskets to maintain a tight seal.

These bipolar plates are the most common fuel cell component made with Ulbrich’s precision alloys, but other matching metal parts are also available.

What are the key material properties needed to optimize fuel cell applications?

Fuel cells become extremely hot during operation and their environments are very corrosive. The durability of materials in these harsh conditions is crucial for this market.

Austenitic stainless steel alloys, composed of at least 8% nickel and resistant to extreme temperatures and corrosion, are generally used in fuel cell applications. Secondary treatment by part manufacturers is common to impart greater corrosion resistance to alloy fuel cell parts.

Specialty metals resistant to corrosion and temperature, such as nickel 200 and 201, are also frequently used in fuel cell designs.

Alloys:

The thickness of the alloy is another key element. More power-generating fuel cell membranes can be stacked if the bipolar plates are thinner, producing a more efficient system that can meet higher voltage requirements.

As these alloy plates are stacked, tight tolerances and flatness are essential to ensure the system operates at peak performance. The slightest inconsistencies are amplified exponentially with each cell, and if the accuracy is not there, the fuel cell can tilt. Tight tolerances are also critical for the secondary processing performed by fuel cell part manufacturers.

Particular attention is paid to how distinctive surface finishes will influence fuel cell reliability and efficiency, as different applications and various fuel cell technologies require different bipolar plate finishes.

The impact that surface finishes can have on corrosion resistance alone means how important it is to source fuel cell materials from suppliers with state-of-the-art surface control capabilities. technology.

Precision winders offer greater control over surface finishes compared to sourcing directly from a smelting mill. For example, Ulbrich works with its customers to offer a variety of application- and process-specific custom finishes that are also specialized for the task at hand.

Typically measured in RA, RY, and RZ (assessing the different aspects of a surface’s peaks and valleys), accuracy is key to ensuring numbers remain consistent across the length and width of the material. This helps create a uniform, consistent surface finish that provides engineers and fuel cell manufacturers with predictable performance reliability.

Although each fuel application varies, there are different considerations that must be taken into account for each alloy used. Gas diffusion, longevity, electrical conductivity and other vital performance factors can be affected by the condition, finish and gauge of any alloys used.

What materials are used to make fuel cells?

Image Credit: Ulbrich Stainless Steels and Specialty Metals, Inc.

What should I look for when choosing a fuel cell material supplier?

Capacity and availability are of utmost importance in the fuel cell market.

Fuel cell applications can differ greatly, therefore a precision winder with the technical capabilities and metallurgical expertise to tailor alloy solutions to your particular application needs is required. If necessary, they should be equipped to assist technical teams in research and development as various material properties and variables are tested.

When it comes to accessibility, selecting a material supplier who can supply a wide range of readily available alloys will help ensure that the optimum grade is available for a given application.

At Ulbrich, close technical collaboration between metallurgists and product development teams paves the way for success. Once the optimum material characteristics have been determined, Ulbrich’s tight control of tolerances, extensive range of finishes, wide selection of alloys and efficient manufacturing processes lead to consistent production of bespoke products for the specific needs of each different fuel cell application.

Distribution centers at the Ulbrich Service Center allow the company to increase its precision rerolling capabilities and provide a consistent supply of materials to fuel cell customers, including wide and narrow products. thickness from the Californian site of Ulbrich.

If you are a fuel cell manufacturer or parts manufacturer, contact Ulbrich to learn how advanced fuel cell material expertise and manufacturing capabilities can support your application.

This information was obtained, reviewed and adapted from materials provided by Ulbrich Stainless Steels & Special Metals, Inc.

For more information on this source, please visit Ulbrich Stainless Steels & Special Metals, Inc.

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