ADVANCED MATERIALS AND CHEMICALS

Maxwell Technologies (formerly Maxwell Energy Products, Inc.)

Superior, More Affordable Ultracapacitors

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In the late 1990s, the power demands of many commercial systems and products, including personal communication devices, electronic games, hybrid vehicles, and industry production lines, were increasing to the point that they were approaching or exceeding battery power limits. As these products and processes became increasingly sophisticated and complex, they also became vulnerable to power surges, dips, and outages. Many of these products and processes use ultracapacitors to assist the batteries or battery systems in eliminating or reducing disruptions. Ultracapacitors supplement batteries to provide constant, sudden, or backup power to prevent service disruption. However, existing ultracapacitors were expensive and increasingly unable to satisfy the backup power and/or energy requirements for the next generation of product lines and manufacturing systems.

Maxwell Energy Products, a producer of ultracapacitors, applied for Advanced Technology Program (ATP) funding under the 1998 “Premium Power” focused program to develop superior, less expensive ultracapacitors. Maxwell turned to ATP after failing to secure private sector funding because of the project’s high technical risk. After gaining ATP support, Maxwell worked from November 1998 to May 2001 to develop superior ultracapacitor technology. The company’s goals were to 1) triple the energy and power of its existing ultracapacitors, and 2) reduce the cost of these ultracapacitors by two-thirds. Project success would involve developing improved ultracapacitor materials and implementing new production techniques. At the conclusion of the project in 2001, Maxwell had succeeded in doubling the power of ultracapacitors, reducing material and production costs by three-fourths, and introducing an advanced line of ultracapacitors. The project also resulted in seven patents and several post-project articles.

As of 2006, Maxwell Technologies (which had changed its name in 2004) was manufacturing a number of products that were a result of the ATP-funded project research, including small, large, and modular ultracapacitor systems. Maxwell ultracapacitors are currently used in hybrid buses, automatic meter-reading systems, industry production lines, and even a U.S. military application. A potential application of Maxwell ultracapacitors is the developing U.S. hybrid and electric car and truck market.

COMPOSITE PERFORMANCE SCORE
    (based on a four star rating)
* * *
Research and data for Status Report 98-03-0050 were collected during April 2006.

Ultracapacitor Technology Lags Behind Advances in Electronics Often referred to as “energy in a box,” ultracapacitors are composed of two electrodes or plates (one positive and one negative surface) immersed in an electrically conductive solution (electrolytes), with a separator that does not conduct electricity. Ultracapacitors store

energy by the activation of the electrolytic solution (typically a salt solution) and then release this energy when electrons, produced by the electrolytes and gathered at the electrodes, transmit energy via the current collectors. Ultracapacitors are used to assist and extend the life of conventional batteries or battery systems by “evening

out” electricity flow when there is a sudden, heightened, or continuous demand for power by a particular product, such as a vehicle or electronic device or a manufacturing line. Compared to batteries and conventional capacitors, ultracapacitors have more power (constant activity) than capacitors but less energy (length of activity) than batteries. The two common cell sizes for ultracapacitors are small and large. Small-cell ultracapacitors supply between 4 and 10 farads^1 of power and weigh from 4 to 6.3 grams. They can be used in hand-held electronic devices, computers, and small toys. Large-cell ultracapacitors supply between 140 and 2,700 farads of power and weigh from 60 to 725 grams. Their shapes can be cylindrical, like a short, flashlight battery, or rectangular. Large-cell ultracapacitors are used in cars, trucks, and buses. They are sometimes joined to form what is called a module, or a group of large ultracapacitors assembled to function as a single source of energy. Modules can be used in industrial or manufacturing environments, and can even supply backup power to various assembly lines. Figure 1 depicts a basic ultracapacitor module, a schematic of the module, and the internal elements of an ultracapacitor. Figure 1. The inner workings of an ultracapacitor. In the late 1990s, the U.S. consumer electronics and manufacturing industries were facing the rapidly expanding need for higher power and energy but lower cost ultracapacitors. Products relying on battery power, such as cellular telephones and computers, were becoming increasingly sophisticated and more sensitive to power surges and disruptions. Even industrial production lines, which were becoming more automated and complex, were increasingly susceptible to even the slightest of power outages, disturbances that led to service disruptions and production downtime. Essentially, technological advances were out-stripping

state-of-the-art ultracapacitors. At the same time, the high cost of ultracapitators, due to out-of-date manufacturing techniques and high material costs, were making ultracapacitors impractical for mass use. Maxwell Proposes More Reliable, Low- Cost Ultracapacitors Maxwell Energy Products was an 800-employee company with a history of investing in and advancing the ultracapacitor market. Throughout the early and mid-1990s, they developed lower cost, higher voltage ultracapacitor cells and modules. But by the late 1990s, the company wanted to develop a new type of ultracapacitor capable of achieving greater power and higher energy, with a significantly lower production cost to meet the needs of American industry and consumers. In the late 1990s, the U.S. consumer electronics and manufacturing industries were facing the rapidly expanding need for higher power and energy but lower cost ultracapacitors. Developing a new ultracapacitor would require making improvements in the unit’s individual elements: electrodes, electrolytes, and separators. Because technical success in improving all these elements could not be assured, Maxwell was unable to secure private financing. In April 1998, the company applied for ATP funding under the “Premium Power” focused program, which sought to promote accelerated progress in the areas of information systems, telecommunications, and the distributed electric power industries. This program supported power-quality-sensitive industries. These industries, which were heavily reliant on the most advanced sources of energy, included digital, broadband, multimedia communications, and computing; mobile electronics; dispersed fiber or wireless low earth orbit satellite-based transmission networks; and distributed electric power. In September 1998, Maxwell was awarded ATP funding for a 2.5-year project. Project Goals Target Performance and Cost Maxwell’s overall goals for the project were to triple the energy and power capabilities of ultracapacitors while

¹A farad is equivalent to 1 amp of current for 1 second at 1 volt. A single AA battery would be equivalent to about 10,000 farads.

reducing production costs by two-thirds. Tripling the energy and power meant, in part, moving ultracapacitors from the range of 1.8–2.4 volts to 3.5–4.0 volts. A tripling of energy and power, if obtained, would be an extraordinary accomplishment. Further, the company sought to reduce the cost of production and materials for its large-cell ultracapacitors from $200 to $67 per unit. Products targeted to benefit from these technology improvements included Maxwell’s PC10 ultracapacitor for consumer products, the PC7223 for the automotive industry, and the PCM150056 modules designed for industrial manufacturing applications. These ultracapacitors featured carbon cloth electrodes, an aluminum case, a polypropylene separator, and an organic electrolyte. The project would focus on improving each of these ultracapacitor elements. To achieve their performance and cost goals under the ATP-funded project, Maxwell divided the work into two categories: 1) the Hybrid program, which would focus on designing new cells that had higher energy and power but lower materials cost; and 2) the Veloce program, which would focus on efficient assembly and consistent manufacturing. Maxwell expected that low-cost materials and effective manufacturing techniques developed in the Hybrid and Veloce programs would produce superior products with a significantly lower per-unit cost. Maxwell’s overall goals for the project were to triple the energy and power capabilities of ultracapacitors while reducing production costs by two-thirds. Maxwell began work on this project in November 1998. The following is a summary of the major, specific tasks and results of the Hybrid and Veloce programs. Subcontractor Sandia National Laboratories worked with Maxwell on electrode and electrolyte development, while the Tennessee Center for Research and Development tested the new ultracapacitors. Hybrid Program Under its Hybrid program, Maxwell sought to improve the quality and performance of individual ultracapacitor elements while simultaneously reducing the cost of the

materials used for these elements. Researchers wanted to achieve increased voltage or energy through the development of an advanced electrode design, a new salt solution for the electrolytes, lower cell resistance, and new separator technology, as described below. Such advancements were considered high-risk research because each improvement required superior ultracapacitor performance using new, low-cost concepts and materials. · Electrode Development. In both large- and small-cell ultracapacitors, Maxwell focused on efforts to couple a lithium negative electrode with a double-layer capacitor positive electrode. Joining these two types of electrodes would increase the energy and operating voltage. Result: Researchers successfully combined a new graphite lithium negative electrode with a new, thinner, double-layer, carbon cloth product as a positive electrode. This new high-power positive electrode allowed more electrically charged ions to form on the current collectors, which increased power performance by a factor of 2 to the 2.7–2.8-volt range. · Electrolytes (solution of salts in water). Maxwell compared the resistance and capacitance constants of different water and salt combinations at different temperatures. Researchers wanted to find a new electrolyte solution that produced higher levels of electrical conductivity. Result: Researchers developed a new salt solution (triethylmethyl ammonium tetrafluroborate in carbonate solvent) that produced active electrolytes with higher conductivity. Furthermore, the solution was less expensive to produce than the current solution used in baseline ultracapacitors. This improvement lowered the cost of the ultracapacitor and did not increase electrical resistance. · Levels of Resistance. Improved electrode and electrolyte developments led to decreased and stabilized electrical resistance. The challenge of further lowering resistance lay in addressing the poor adhesion of the active electrode. Maxwell’s objective was to increase the number of electrically charged ions or electrolytes “sticking” to the new graphite carbon cloth electrodes or current collector plates.

Result: Researchers solved the problem by interposing a new primer coating on the current collector, which lowered resistance and cost. Adding this primer coating increased the life cycle of the ultracapacitor by 10 to 20 percent, thereby lowering the cost of ultracapacitor energy. · New Separator Technology. State-of-the-art ultracapacitors used polypropylene-type separators. These separators had extremely fine pores to prevent carbon fibers from penetrating and causing micro-electrical shorts. Polypropylene separators proved effective, but were composed of expensive materials. Result: After experimenting with numerous types of separators, researchers determined that paper separators were an acceptable and far less expensive option. The new paper separator was 1/6 the cost and caused no performance degradation. Veloce Program The Veloce program was established as an integral part of the ATP-funded project to address the goal of increasing levels of energy in ultracapacitors. Based on this objective, the program introduced a new and superior process for manufacturing ultracapacitors and sought to develop more efficient ultracapacitor cell designs. The new manufacturing process would seek to reduce voltage leakage rates by at least 30 percent (achieved by limiting exposure to assembly line contaminants) and improve product yields above 50 percent. Development of module cells focused on creating a variety of structural designs that could easily configure to different voltages and capacities. Developing an efficient and flexible production line and new designs would increase the speed of market acceptance of the advanced ultracapacitor models. The Veloce program objectives and results are described below. · Demand-based flow manufacturing. Demand-based flow manufacturing was introduced into the Maxwell production scheme for assembling ultracapacitors. Demand-based flow manufacturing is a proven, high-velocity supply chain technique that drastically reduces unit production time and therefore increases competitive edge by responding more quickly to market demands. In a demand-

based flow manufacturing environment, inventory is "pulled" through each production work center only when needed to satisfy a customer requirement. As a result, the entire supply chain must be configured for maximum flexibility and quick response so that custom orders can be filled as quickly as a standard item. Result: Implementing the demand-based flow manufacturing plan significantly reduced leakage current in the large-cell ultracapacitors by successfully reducing exposure to contaminants. Leakage current is the residual flow of current through a device’s insulation after voltage has been applied. A manufacturing process with minimal production stages and assembly time can lower the levels of current loss. Leakage was lowered by 50 percent, from approximately 50 microamps to 25 microamps, after 11 hours of charge following demand-based implementation. The lower leakage increased ultracapacitor yields dramatically, from 11 percent to 65 percent. Overall, the cycle time for the production of an ultracapacitor dropped from an average of 40 days to 2 days. Implementation of demand-based flow manufacturing allowed Maxwell to achieve a $50/cell production and material cost for its large-cell ultracapacitors. This level represented a 75% reduction in cost over the baseline cell, exceeding the company’s project goals. · Low-cost ultracapacitor modules and new large-cell products. Maxwell sought to develop new, more efficient ultracapacitor modules from the ATP-funded technology. Module systems are needed to assist manufacturing production lines and plant operations. Result: As a result of Maxwell’s technical innovations, the company developed new, high-energy 56-volt and 650-volt module systems. The 56-volt module represents a 40-percent reduction in volume and a 25-percent reduction in weight over the baseline module. This system is equipped with 28 PC7223 PowerCache ultracapacitors. The 650-volt system, called the Ride-Through-System, combines eight 56-volt ultracapacitor modules. Maxwell applied these technological and manufacturing successes to their existing line of ultracapacitors. The combination of ultracapacitor material development with

new production line processes proved highly successful. Maxwell was able to significantly upgrade its existing models into the redesigned and renamed PC2500, PC5, and PC10 lines of ultracapacitors. Achievements in Hybrid and Veloce Lead to TeraCap Beginning in the first quarter of 2000, Maxwell took advantage of technical and production achievements in the ATP-funded project and applied them to another ultracapacitor area: cylinder or battery pack D-cell ultracapacitors. Maxwell named this spillover application and new product line “TeraCap” technology. The TeraCap ultracapacitor was composed of a spiral-wound carbon powder and aluminum foil electrode in an extended foil jellyroll. The electrode assembly could be encased and compressed into a small package, one-third as tall as a AAA battery. The new Maxwell TeraCap ultracapacitor had 4 farads, 0.125 ohm capabilities and, in 2001, was the highest energy-density ultracapacitor commercially available, with twice the available power of other units. The TeraCap was capable of being used in a variety of ultracapacitor products and could be produced at $ 0.17 per unit. This effort was executed and funded exclusively by Maxwell. New Ultracapacitor Technology Enters the Market By the end of the ATP-funded project in May 2001, Maxwell had successfully developed new materials, superior manufacturing processes, and new products allowing for the development of improved and less expensive ultracapacitors. Technological breakthroughs in low-cost, well-performing electrodes, separators, and electrolytes, as well as improvements in resistance, led to the development of new products. These improved ultracapacitors were being produced using the more efficient demand-based flow manufacturing. Maxwell was able to produce ultracapacitors at lower costs in 2001, including its new PC2500, PC5, PC10, and TeraCap products. These successes also led to seven patents and a number of post-project articles. In June 2002, Maxwell Technologies acquired Montena Components, Ltd., a Swiss manufacturer and distributor

of capacitors and ultracapacitors. This move accelerated the development of the ATP-funded technology by solidifying Maxwell’s place as one of the world’s top producers of ultracapacitors. The acquisition brought together Maxwell’s low-cost, high-performance electrode technology and manufacturing advances with Montena’s packaging and assembly abilities. Shortly after this acquisition, Maxwell changed the name of its ultracapacitor products to Boostcap technology. Technological breakthroughs in low-cost, well-performing electrodes, separators, and electrolytes, as well as improvements in resistance, led to the development of new products. As of 2006, Boostcap PC2500, PC5, PC10, and BCAP2600 ultracapacitors were being used in both industrial (for example, in electric meter-reading systems and pulse-tracking devices) and transportation (for example, hybrid or electric vehicle) markets. The BCAP2600, depicted in Figure 2, is ideal for industrial and hybrid or electric vehicle applications. Like all ultracapacitors, it can be used with a number of primary power supplies, such as battery, fuel cell, or generator. The BCAP2600 provides industrial plants and hospitals with a constant flow of power. However, the primary focus of large-cell ultracapacitor technology is in the transportation sector: hybrid or electric cars, trucks, buses, and trolleys. One of the more impressive uses of the BCAP2600 is to provide energy storage and support in hybrid buses. ISE Research in San Diego, California uses Maxwell’s ultracapacitors in the Thunderpack energy systems in its 18 hybrid-electric buses. The BCAP2600 performs better, costs less, is recyclable, and even increases safety by eliminating the often hazardous reliance on conventional chemical-based batteries in each vehicle. However, inroads into the hybrid and electric bus market aside, limited development and production within the U.S. hybrid-electric car and truck manufacturing sector has severely dampened wide commercialization of large-cell Maxwell ultracapacitors. But as this potentially important sector of vehicle manufacturing matures, use of Maxwell untracapacitors is expected to increase.

Figure 2. Maxwell BCAP2600 Boostcap ultracapacitor. The PC5 and PC10 ultracapacitors are well suited for consumer electronics, wireless transmission, medical devices, automatic meter readers, and other applications in which a battery or power supply alone cannot provide a constant and long pulse of energy. The PC5 and PC10 are able to deliver more energy during sags or outages of battery power. One of the more intriguing uses of the PC10 is in automatic meter-reading systems. Tantalus and SmartSynch Corporations use the PC10 in its automatic meter-reading systems, which help electric utilities to more efficiently monitor and measure electrical current and usage. Providing increased pulsed power capabilities, ultracapacitors are used in rural, urban, residential, and commercial unmanned monitoring stations that supply two-way, real-time data on power usage and outages. Figure 3. Maxwell PC5 ultracapacitor. Additionally, two PC5s, depicted in Figure 3, are used in Boeing’s Combat Survivor Evader Locator (CSEL) communications system. This system is being used by

some U.S. military branches to help locate downed pilots and their aircraft when they are lost in combat. Conclusion In November 1998, Maxwell Energy Products (later renamed Maxwell Technologies) began an ATP-funded project under the “Premium Power” focused program. The company sought to improve the performance and lower the cost of ultracapacitor products. By the end of the project in May 2001, the company had met or exceeded many of its technical and development objectives as well as its overall performance measurements, including developing a new line of ultracapacitors. The superior line of ultracapacitors featured less expensive materials. These advanced ultracapacitors were assembled along a more efficient manufacturing line, leading to low-cost small, large, and modular unit ultracapacitors. The success of this project resulted in seven patents and the publication of several articles. In 2002, Maxwell acquired Montena Components, a strategic move that solidified Maxwell’s place in the ultracapacitor field. Maxwell continued to advance and develop the ATP-funded technologies. As of 2006, Maxwell Technologies was marketing its original ATP-funded technical advancements and achievements as their Boostcap ultracapacitors. These ultracapacitors feature a high degree of adaptability and support, and they even extend the life of batteries and battery-powered products. Overall, Maxwell improved the quality of ultracapacitors and simultaneously reduced the cost dramatically. Application of this new line of ultracapacitors extends into the consumer products, commercial, industrial, transportation, and military sectors. However, due to the slow development of the U.S. hybrid and electric car and truck markets (as well as the low cost and relative effectiveness of batteries in consumer electronics), overall market demand for ultracapacitors, when compared to batteries, remains exceptionally low. Yet, Maxwell Technologies is in a position to serve as a leader in supplying the U.S. consumer and manufacturing sectors with the next generation of ultracapacitors.

PROJECT HIGHLIGHTS
Maxwell Technologies (formerly Maxwell Energy Products, Inc.)

Project Title: Superior, More Affordable Ultracapacitors (Advanced Materials and Processes for Cost-Effective High-Power Ultracapacitor Modules) Project: To develop new materials and manufacturing processes to improve the performance and reduce the cost of ultracapacitors, which could save U.S. industry billions of dollars in lost productivity, reduce fuel consumption in vehicles, and extend the life of electronic devices. Duration: 11/1/1998 - 5/31/2001 ATP Number: 98-03-0050 Funding (in thousands): ATP Final Cost              $2,000    47.4% Participant Final Cost        2,219    52.6% Total                            $4,219 Accomplishments: With ATP funding, Maxwell Energy Products, Inc. (later renamed Maxwell Technologies) reduced the cost of its next line of marketable ultracapacitors by 75 percent and improved efficiency by 50 percent. Maxwell’s specific accomplishments were: · Increased the power and energy of existing ultracapacitors from 1.8–2.4 volts to 2.7–2.8 volts · Reduced the materials and production costs of its large-cell ultracapacitors from $200 to $50 per unit · Developed a new, superior line of affordable cylinder, battery pack D-cell ultracapacitors Maxwell received the following patents for technologies related to the ATP-funded project: · "Multi-electrode double layer capacitor having single electrolyte seal and aluminum-impregnated carbon cloth electrodes” (No. 6,233,135: filed August 18, 1999, granted May 15, 2001) · "Multi-electrode double layer capacitor having hermetic electrolyte seal” (No. 6,449,139: filed August 18, 1999, granted September, 10, 2002)

· "Electrochemical double layer capacitor having carbon powder electrodes” (No. 6,627,252: filed May 12, 2000, granted September 30, 2003) · "Method of making a multi-electrode double layer capacitor having single electrolyte seal and aluminum-impregnated carbon cloth electrodes” (No. 6,451,073: filed May 16, 2000, granted September 17, 2002) · "Low resistance bonding in a multi-electrode double layer capacitor having single electrolyte seal and aluminum-impregnated carbon cloth electrodes” (No. 6,430,031: filed February 12, 2001, granted August 6, 2002) · "Method of making a multi-electrode double layer capacitor having single electrolyte seal and aluminum-impregnated carbon cloth electrodes” (No. 6,585,152: filed February 13, 2001, granted July 1, 2003) · "Electrochemical double layer capacitor having carbon powder electrodes” (No. 6,643,119: filed November 2, 2001, granted November 4, 2003) Commercialization Status: The Maxwell PC2500, PC5, PC10, and BCAP0350 products are a direct result of the ATP-funded project. The products are used as follows: PC2500 in hybrid buses, the PC10 in meter-reading systems, the PC5 in pulse-tracking devices, and the BCAP0350 for industrial and hybrid or electric vehicle applications. Outlook: The outlook for Maxwell Technologies is uncertain. While the project experienced a high degree of technical and production success, unfavorable market conditions continue to stifle large-scale commercialization of Maxwell ultracapacitors. The U.S. hybrid and electrical vehicle industry, as of 2006, is in its nascent stage and has yet to command a large portion of the car and truck production market. Additionally, rapid product-to-market demand in the personal communication device arena has hindered Maxwell’s ability to promote ultracapacitor use in this industry. Despite impressive reductions in cost, ultracapacitor product cost must be lowered further,

PROJECT HIGHLIGHTS
Maxwell Technologies (formerly Maxwell Energy Products, Inc.)

because batteries, while limited in their effectiveness and durability compared to ultracapacitors, are a far cheaper source of energy. Composite Performance Score: * * * Focused Program: Premium Power, 1998 Company: Maxwell Technologies 9244 Balboa Avenue San Diego, CA 92123-1514 Contact: Bobby Maher Phone: (858) 503-3325 Subcontractors: · Rees, Sandia National Laboratories Albuquerque, NM · Tennessee Center for Research and Development Knoxville, TN

Publications: · Chin, Spencer. “Maxwell to Energize Vehicles – GM to Use Ultracapacitors in Hybrid Engines.” CMP Media, January 22, 2001. · “Simplified Design Widens Applications.” Battery and EV Technology, Vol. 27, June 2002. · Roos, Gina. “Large Supercaps Steer toward Auto Applications.” Electronic Engineering Times, June 3, 2002. · “Maxwell Technologies Agrees to Acquire Montena Components; Combination Will Solidify Global Ultracapacitor Leadership.” PRNewswire, June 3, 2002. · Hubbard, David. “A Breakthrough in Hybrid Energy Storage.” BUSRide Magazine, September 2005. · Smith, Richard E. “Ultracapacitors Enable Distributed Automotive Power.” Automotive Design Line, September 12, 2005. · Auer, Juergen, and Adrian Schneuwly. “Ultracapacitors Meet Automotive Power Supply Challenges.” Passive Component Industry, January/February 2006.

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Research and data for Status Report 98-03-0050 were collected during April 2006.