SGL Carbon

Graphite is offered moreover in flexible sheets (e.g. Sigraflex of the SGL-Carbon Group). This is primarily a sealing material, but it is suitable also as electrode or corrosion resistant current feeder (erosion in case of gas evolution is possible). 

In another report, James and Kalinoski [4] performed an estimation of the costs for a direct hydrogen fuel cell system used in automotive applications. The assumed system consisted of an 80 kW system with four fuel cell stacks, each with 93 active cells this represents around 400 MEAs (i.e., 800 DLs) per system. The study was performed assuming that the DL material used for both the anode and cathode sides would be carbon fiber paper with an MPL. In fact, the cost estimate was based on SGL Carbon prices for its DLs with an approximate CEP value of around US 12 m for 500,000 systems per year. Based on this report, the overall value of the DLs (with MPL) is around US 42.98 per kilowatt (for current technology and 1,000 systems per year) and 3.27 per kilowatt (for 2015 technology and 500,000 systems per year). Figure 4.2 shows the cost component distribution for this 80 kW fuel cell system. In conclusion, the diffusion layer materials used for fuel cells not only have to comply with all the technical requirements that different fuel cell systems require, but also have to be cost effective. 

Lin and Nguyen [108] did an extensive study on the effect of the PTFE content on the performance of Toray and SGL Carbon SIGRACET carbon... 

SAMSUNG ELECTRONICS CO LTD SGL CARBON AG SHARP CORPORATION SHELL OIL CO SIEMENS AG SIGMA-ALDRICH CORP SKYPOWER CORP SOLARGENIX ENERGY LLC SPIRE CORPORATION SULZERLTD... 

Data sheet from SGL Carbon Group, SIGRASIC 6010 GNJ — Faserverstarkte Keramik fiiir Bremsscheiben (1998). 

Figure 2.11 Typical manufacturing process for molded graphite. Source Reprinted from SGL Carbon Group technical literature, Carbon and Graphite Manufacture and Properties, 1995.

Dow Chemical Co., Asahi Chemical Co. and Chloride Engineers Ltd. make a similar product. The polymer membrane only conducts H" " when fully hydrated and one solution to this problem has been to use carbon fiber wicks (Figure 23.9). SGL Carbon is making fiber based gas diffusion layers in a roll form. The cell is sensitive to low levels of CO, which can be removed by a Pt/Ru catalyst, but the high cost restricts use. However, a later technique to increase the surface area has reduced the cost by a factor of 75. 

BP Chemicals (Hitco) Inc., Gardena, California, USA—British Petroleum (BP), UK acquired Bristol Composite Materials in 1979, but sold to GKN-Westland in 1997. In 1986, acquired Hitco from Owens Corning and sold to SGL Carbon in 1997. BP Amoco s carbon fiber business was sold to Cytec Fiberite in September, 2001. 

Selcom SRL, Fregona (TV), Italy—produce UD and multidirectional carbon fiber fabrics. SGL Carbon Composites, Gardena, California, USA—formerly Hitco Technologies, acquired by SGL Carbon in 1997. Specialises in carbon-carbon composites and is the largest producer of carbon-carbon brakes. 

Ticona has co-operated with SGL Carbon to produce a graphite-filled liquid crystal polymer, also for fuel cell plates. There are likely to be 200 bipolar plates for each cell, and two cells per vehicle. The filled polymer is meant to be injection moulded, but this requires much higher throughputs than compression moulding to be economic. 

Table 10.10. Properties of industrial graphite grades from SGL Carbon...

SGL Carbon Group, http //www.sglcarbon.com/sgl t/fibers/sigra c.html. 

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