Non-coating metallic bipolar plate for polymer electrolyte membrane fuel cell

Technology overview: Fuel cell bipolar plate is a component that plays significant roles in supplying gases for the reaction of unit cells, and in collecting the electricity within fuel stacks with a layer of dozens to hundreds of unit cells. In the early stage of the development of fuel cell, graphite bipolar plates were used. However, problems with graphite plates include brittleness and the cost. So, metal bipolar plates have gained attention for cheap expenses and the outstanding formability for multiple applications. However, because metals are subject to corrosion and lower conductivity, a coating must be applied to provide a protective layer with high corrosion resistance. This makes the bipolar plate process more complicated and more expensive. To solve such problems, POSCO developed stainless steel Pos 470FC that could make it possible to produce non-coating metal bipolar plate for polymer electrolyte membrane fuel cell (PEMFC). This technology is composed of two technologies: one is to develop materials with high corrosion resistance in corrosive environments through excellent corrosion-resistant stainless alloy; the other is to produce materials with excellent conductivity while maintaining the lower conductivity of the outer layer to the point of having higher corrosion resistance. In addition, the company employed sheet forming technology such as stamping to develop the process technology for the component production of fuel cell bipolar plates. By verifying the long-term durability of fuel cells (25,000 hours for building, 5,700 hours for transportation), it established a base technology that could innovatively reduce manufacturing costs of bipolar plates and accelerate the commercialization of fuel cells.

Untitled-5.jpgIndustrialization: In 2012, POSCO employed non-coating metal bipolar plate using structural steel in cooperation with Doosan Fuel Cell (formerly Fuel Cell Power) for the first time in the world, thus succeeding in producing 1kW stack and obtaining the certificate of new & renewable energy system from the Korea Energy Management  Corporation. In particular, coupled with the development roadmap for eco-friendly vehicles of global automobile companies, the company is in cooperation with bipolar plates for fuel cell vehicles. To promote the strategic items of core materials and components for exports, it is developing a commercialized technology that corresponds to the mass production. In particular, the industrialization of forming parts as well as materials is underway by packaging material technology with fuel cell bipolar plate applied to ultra-thin plate, which was jointly developed with small & medium-sized enterprises. The core material & parts of fuel cell is expected to develop as an export item.

Problem-solving in industrialization: In fuel cell operating environments, POSCO achieved world-class high corrosion resistance and conductivity without the conventional coating process, while the company found it difficult to form a complicated shape of bipolar plate made of ultra-thin plate of 0.1 mm in thickness compared with general stainless steel. Based on the close collaboration with small & medium-sized enterprises, universities, and research institutes, it obtained materials forming technology in a short time by taking systematic approaches such as optimal Channel design, forming interpretation, and forming test. In this process, it discovered many small and medium-sized companies with excellent competency. Based on such efforts, POSCO laid the foundation for a technical base that could provide not only materials for fuel cell bipolar plate but also its application technology and in turn, successfully achieving industrialization.

Technology developer: POSCO / +82-54-220-9849 / | Blog Magazine of korean-machinery, brands and Goods

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