Phase-outs of Fossil Fuel VehicleS are accelerating. Photo Credit: Blowberg Report "Electric Vehicle Sales Headed for Five and A Half MilLIP;", November 202111211

　　Global Monthly Ev Sales Show 57% in 2022. Photo Credit: https://www.ev- volumes.com/

　　2050, 60% of New Passenger Vehicle Sales Must Be Zero-Emission Vehicles (ZEV) by 2030 and 100% by 2035.

　　Create Material Cards (for USE in Simulation Software) for its Higher Volume Materials to Help its Customers Develop New Products.

　　Patent-Pending Multi-Material Enclosure Solutions Feature FR Composite Covers and Hybrid Traminum and Composites.

　　Impregnated with either phenolic or a high-testure fr epoxy for high-Pressure RTM, Wet Composite Molding and Other TechNologies.

　　Tier supplier Kautex Textron GmbH & Co. KG (Bonn, Germany) worked with materials supplier Lanxess AG (K?ln, Germany) to explore using thermoplastic composites to replace steel and aluminum on large-format EV battery enclosures. For a C-segment (mid -size) sedan, the partners demonstrated a 1,400- × 1,400-millimeter battery enclosure comprising a tray connected to an integral crash structure and underbody protection plus top cover. Components were made using Durethan B24CHM2.0 fiberglass-reinforced PA6 using compression D-LFT (long fiber thermoplastic), a one-step process well suited to producing large parts quickly and affordably. The tray’s crash structure was locally reinforced with Tepex dynalite continuous fiberglass-reinforced PA6 to meet high structural requirements. As well as being heavy, metal housings are expensive due to the size, number of components and many manufacturing and assembly steps — including welding, punching and riveting. They must also be protected against corrosion by cathodic dip coating. Alternatively, composites are corrosion resistant and electrically insulating, which reduces risk of short circuiting. They also enable integration of fasteners and thermal-management components, which reduces the number of components and simplifies assembly and logistics, reducing cost and weight.

　　Performance. He Notes That Despite SMC & RSquo; S Higher Initial Material Costs, Compression Tooling is Less Costly for Program<50,000 units/year compared with multipiece metal stampings, castings and extrusions that must be machined, coated and assembled. Versus steel stampings, for example, tooling cost savings are typically 35% for 30,000 parts/year and 20% savings for 40,000 parts/year.

　　Thermoplastic composites in battery enclosures. A and B sides of production EV battery cover compression molded in GMT and GMTex organosheet composites. Photo Credit: Mitsubishi Chemical Advanced Materials

　　Mitsubishi Chemical Group Corp. (MCG, Tokyo, Japan) has supplied materials into composite EV battery enclosures globally, including its GMT and GMTex materials. The company is developing innovative multifunctional materials to withstand thermal runaway events, like a new FR thermoplastic composite for battery enclosures that has passed tests exceeding a five-minute exposure to a 1,000°C flame. It is also exploring the use of bio-based thermoset resin systems for its glass and carbon fiber-reinforced prepregs.

　　Integrated intumescent FR battery box cover. The 1.6- × 1.4-meter cover — made from a short glass fiber-reinforced PP compound with intumescent fire resistance for an EV manufactured by Honda in the Chinese market — is one of the industry’s largest and reportedly first featuring polymer materials to pass the demanding China GB 18384-2020 spec. Photo Credit: SABIC

　　SABIC (Riyadh, Saudi Arabia) supplied the FR short glass fiber-reinforced polypropylene (PP) resin in one of the industry’s largest battery covers for a Honda Motor Co. (Minato City (Tokyo, Japan) EV in the Chinese market. The compound was formulated to form an intumescent char when exposed to flames, enabling self-extinguishing behavior. It was the first cover to pass the new China GB 18384-2020 spec.

　　Compared to metallic battery enclosures — where required thermal blankets add significant weight, cost and environmental concerns — SABIC’s injection molded thermoplastic delivers 40% weight savings, helping to extend driving range, while functional integration simplifies assembly and reduces cost. The part can also be fully recycled at end of life (EOL) and has a smaller CO2 footprint. SABIC sees FR thermoplastics potentially grabbing a larger share of battery enclosures because they offer inherent thermal and electrical isolation, intumescent qualities, lightweighting, parts integration and potentially parts elimination, which supports cost reduction. For example, battery trays have been explored where molded-in cooling channels enable 60-kilogram weight savings and 50% cost savings.

　　In December 2021, AZL Aachen (Germany) completed a one-year project on multi-material battery casing designs, leading a consortium of 46 industrial partners. Five sub-components of a battery casing were defined: enclosure tray, bottom protection plate, crash frame, cross beams and enclosure lid or cover. The partners analyzed a total of 44 market-relevant, existing series components and concepts in more detail and compiled a comprehensive overview of standards and requirements at national, international and OEM levels, with the goal to achieve the same or better mechanical performance than conventional solutions. AZL developed 20 design concepts with different combinations of materials including thermoplastic and thermosets, SMC, pultruded profiles, fabrics, unidirectional (UD) materials, sandwich (foam, honeycomb and D-LFT core), as well as LFT and hybrid overmolding (tape + injection molding). These designs were analyzed by creating more than 500 finite element models and performing more than 1,500 CAE simulations. Results showed that multi-material composites offer weight savings up to 36% and cost savings up to 20% versus conventional solutions. The project set up follow-up projects to be completed in 2022 including fabrication of demonstration prototypes and studies on bottom impact protection and fire resistance.

　　Projected fuel cell growth. Photo Credit: Page 83, Global Hydrogen Review 2021 by the International Energy Agency (IEA), E4tech

　　Fuel cell production capacity was projected to exceed 200,000 systems/year by the end of 2021, supplied by more than 40 manufacturers, according to an analysis by the International Energy Agency (IEA) on page 83 of its report “Global Hydrogen Review 2021” (released and revised in October and November 2021). However, that unit count by IEA is much higher than the ≈86,000 fuel cell shipments reported by energy and sustainability consultancy E4tech (London, U.K.) in its “Fuel Cell Industry Review 2021” published in July 2022.

　　Though market estimates vary, they all project growth. The IEA forecast from 2021 reported that capacity announcements from fuel cell manufacturers totaled 1.3 million systems/year by 2030. A generic “Automotive Fuel Cell Market” report publicized in November 2022 by PRnewswire, and sold by multiple online market research sites, cited 25,000 units in 2022 with growth to 724,000 units by 2030.

　　Growth highlights: Currently listed as the largest fuel cell producer, Plug Power (Latham, N.Y., U.S.) is reported to have a production capacity at its N.Y. gigafactory of 7 million membrane electrode assemblies (MEA)/yr (see “Fuel cell components” section below) and 600,000 fuel cell stacks/year. Toyota (Toyota, Japan) currently has a production capacity of 30,000 fuel cells/year in Japan and is adding capacity at its Georgetown, Kentucky, factory for hydrogen-powered heavy trucks in the U.S. Hyundai (Seoul, South Korea) will add to its current capacity of 23,000 fuel cells/year with two factories in Korea — each with a capacity of 50,000 fuel cells/year — starting production in 2H2023, targeting 700,000 systems/year by 2030. Hyundai also produces 6,500 fuel cells/year in Guangzhou, China. The Michelin/Renault joint venture Symbio (Vénissieux, France) has announced an annual fuel cell production capacity of 50,000 by 2026, 100,000 by 2028 and 200,000 by 2030. Ballard Power Systems (Burnaby, B.C., Canada) is investing $130 million in a new membrane electrode assembly (MEA) plant in Shanghai, China, targeting production in 2025 of 13 million MEAs for 20,000 fuel cell engines annually. Proton Motor Fuel Cell (Puchheim, Germany) is increasing its capacity to 30,000 stacks/year and 5,000 FC engines/year starting Q2 2023.

　　According to E4tech, the fuel cell market comprises three main subsegments classified by application type:

　　Growth in fuel cell shipments. Photo Credit: Page 77 (top) and 78 (bottom), “Fuel Cell Industry Review 2022” by E4tech.

　　Portable — used in small auxiliary power units (APU) for personal appliances and electronics.

Stationary –— used in large prime power applications as well as combined heat and power (CHP) units and larger, permanent APUs.

Transport — where automotive comprises most of the units, but also includes truck/bus, rail, marine, aviation, materials handling and logistic vehicles.

E4tech reports that transport applications lead the overall market in megawatts (MW) while stationary applications lead in fuel cell units shipped.

　　Fuel cells by technology type/electrolyte chemistry. Photo Credit: Page 57 (top) and page 7 (bottom), “Fuel Cell Industry Review 2022” by E4tech

　　These three main subsegments comprise multiple fuel cell types based on the six main electrolytes used: proton exchange membrane fuel cells (PEMFC), direct methanol fuel cells (DMFC), phosphoric acid fuel cells (PAFC), molten carbonate fuel cells (MCFC), solid oxide fuel cells (SOFC) and alkaline fuel cells (AFC). PEMFC (mainly for transport) and SOFC (for portable and stationary) dominate both MW and unit shipments.

　　Carbon fiber composites can be used in various fuel cell components, including bipolar plates, gas diffusion layers (GDL) and end plates. Along with the MEA, bipolar plates and GDL make up the unit cell that is then repeated multiple times to form a stack of cells, book-ended by two end plates. The number of cells in a stack varies according to power produced, application and technology used. For example, Nedstack (Arnhem, Netherlands) uses 48 cells to deliver 6.8 kilowatts of electrical power in its FCS 7-XXL PEM fuel cell, while Bosch SOFC (Stuttgart, Germany) uses 400 cells in its 120-kilowatt solid oxide fuel cell. Note, this is why different factories making millions of MEAs may equate to very different amounts of fuel cell stacks and powerplants/engines.

　　Components of a fuel cell and stack. Photo Credit: Fig. 1.1, “Modelling of thermal and water management in automotive polymer electrolyte membrane fuel cell systems” (top) and Fig. 1.3, “Control of a fuel delivery system for polymer electrolyte membrane fuel cells …” (bottom).

　　As components in the unit cell, multiple sets of GDL and bipolar plates are required per fuel cell stack. As explained in CW’s 2022 plant tour of AvCarb (Lowell, Mass., U.S.), GDLs are thin, highly engineered carbon fiber paper composites, laminated with polytetrafluoroethylene (PTFE) and other coatings. AvCarb’s products are targeted specifically toward PEM fuel cells, using its proprietary carbon fiber graphitization process to produce GDL that help manage reactants in the fuel cell’s electrochemical reactions (read the tour, linked above, for those details) and thus maximize power generating capability.

　　AvCarb GDL products start with oxidized polyacrylonitrile (PAN) fibers that are stretch-broken in a two-step process to produce thick bundles called slivers (pronounced “sly-vers”). These are twisted into smaller-diameter tows or yarns, wound onto bobbins, woven into fabrics and then carbonized and treated in multiple steps to produce a nonwoven that is 99.99% pure carbon. Proprietary coatings are then applied which help the GDL to meet a long list of critical requirements. It has to be chemically inert, electrically conductive, resist physical degradation and be able to compress the right amount, but not too much. Because the fuel cell generates water from hydrogen and oxygen, the GDL must be able to dispel that moisture without drying the MEA, which must stay wet, but not too wet. “In all, it is a very complicated high-performance composite structure that is fully graphitized and unique in the industry,” says AvCarb CEO, Roger Masse.

　　AvCarb doubled its Lowell capacity in 2022 and is planning further expansion globally. It is also accelerating R&D to meet future demands. Masse notes that fuel cell technology is evolving quickly, with a variety of increasingly complex designs entering the market — different shapes, sizes and principles of operation — that demand different GDL features and performance attributes.

　　An alternative manufacturing approach is illustrated by SGL Carbon’s (Wiesbaden, Germany) SIGRACET gas diffusion layers, used by Hyundai Motor Group (Seoul, South Korea) in its PEMFCs for the NEXO fuel-cell passenger car. Microporus backing paper is made by wet laying chopped PAN-based carbon fiber and converted into GDL by applying a carbon-based microporous layer (MPL). The full process is illustrated on the SGL website, and the company has increased production at its Meitingen, Germany facility to support Hyundai and others in the growing fuel cell market.

　　Another well-known player in composites, Technical Fibre Products (TFP, Burneside Mills, Cumbria, U.K.), has also produced GDL for decades. Sharing the same corporate headquarters, TFP Hydrogen began as PV3 Technologies, founded in 2011, and joined TFP Group in 2021. It produces a range of carbon papers which can be tailored to suit the requirements of stationary and portable fuel cell systems, with nonwovens used as a GDL substrate for PEMFC, PAFC and DMFC.

　　Chopped carbon fiber and graphite-filled/vinyl ester bulk molding compounds (BMCs) are finding wide use in bipolar plates for PEMFCs. As multifunctional components, bipolar plates uniformly distribute fuel, gas and air; conduct electrical current from cell to cell; remove heat from the active area and prevent leakage of gases and coolant. Bipolar plates are also key components in electrolyzers, used to produced hydrogen from water, and redox (reduction oxidation) flow batteries used to store renewable energy for later use. All of these applications are targeted for high growth.

　　In the past, thermoset materials were thought to be limited to lower volume and stationary fuel cell applications, due to their longer mold cycle times, higher scrap rates and an inability to produce molded composite plates as thin as stamped metal plates. However, BMC cost has declined significantly as volumes have increased and formulation improvements have shortened molding cycles from minutes to seconds. According to a CW webinar presented by LyondellBasell in 2021, conductive BMC is becoming an alternative to metals in bipolar plates, contributing to lower plate and assembly costs thanks to the material’s inherent corrosion resistance enabling and moldability into complex geometries which reduces machining, coating and other secondary operations.

　　Ultrathin carbon fiber composite bipolar plates. Hycco has developed bipolar plates using a carbon fiber/thermoplastic composite web that is 0.38-millimeter thick. Photo Credit: Hycco copyright 2022

　　Hycco (Toulouse, France), established in 2019, has developed bipolar plates using carbon fiber thermoplastic composites. It claims these are the first flexible carbon fiber bipolar plates available commercially and that a 0.38-millimeter-thick web enables a 1-millimeter-thick plate versus traditional composite bipolar plates at 2 millimeters, cutting weight by 30-50%. The company claims bipolar plates account for 75% of the weight and 30% of the cost of fuel cell stacks, with as many as 600 plates required for a 120-kilowatt fuel cell used in a medium/heavy-duty truck. In 2022, Hycco established a prototype line capable of producing 10,000 bipolar plates/year and is moving toward a pilot line for 250,000 plates/year by 2025, targeting scale-up to >Web Plate Also Been Demonstrated, Opening the Field of a New Generation of Very High Power Density Stacks.