21st International Battery Seminar
and Exhibit, March 8 - 11, 2004

Lawrence A. Tinker, Ph.D.
Battery Industry Consultant
Atlanta, GA

The 21st Annual Battery Seminar and Exhibition opened in the Ft. Lauderdale Convention Center on March 8 with an introduction by Shep Wolsky and Harry Taylor. There were several areas of focus at the seminar, including future power requirements for portable devices, lithium-ion battery safety and new developments, advances in alkaline batteries, and fuel cell developments.

In his opening remarks Taylor commented on the scope of the topics with the following questions to the audience: “Can we make a consumer-safe lithium-ion cell?” “Is lithium-ion at its flattening point in terms of capacity capability?” “How can fuel cells, fuel cartridges, and batteries interact to provide solutions to future needs?” All of these were presented as challenges for focusing the direction of new development in the industry.

The initial papers addressed the market needs for portable power. Kamal Shah of Intel opened the conference proceedings with a presentation on the need for longer battery life. Shah reported on the status of the Mobile PC Extended Battery Life Working Group (EBL WG) formed in late 2002. The group consists of more than 20 companies working to develop guidelines for the mobile PC industry. Currently there is a wireless growth explosion in the mobile PC area. Projections are that wireless will grow at a compound annual rate of >40% through 2008, there will be over 190,000 “hot spots” by 2007, and 89% of mobile computers will be wireless by 2005. All of this is putting additional pressure on the need for longer lasting and higher energy batteries. The key message was that industry-wide collaboration and demonstrated power source innovation are re-quired to address this issue.

Peter Gaucher of IBM discussed the concept of “Pervasive Computing” and how it is driving the growth of mobile devices and globalization of technology. Devices are becoming platforms rather than stand-alones and need to be able to communicate/integrate across a wide variety of applications. The ability to respond in a rapidly changing environment and the need for information that “follows you around” are both driving an explosion in mobile devices. The implications for portable power are the need to develop customized systems that interact with usage patterns and can provide an “invisible” power source to the consumer.

Jason Howard of Motorola reported on the efforts of the IEEE P1625 Working Group to develop system level standards for rechargeable batteries for portable computing. This standard would establish criteria for design analysis for lithium-ion and lithium-ion polymer battery qualification, quality and reliability. It also would provide industry with documented guidance for design of batteries for portable computing, is voluntary, applies to the entire system and not just the battery, and places emphasis on design analysis to incorporate prior knowledge and experiences from industry. The working group consists of more than 15 companies with more than 50 participants. A final draft of the standard has been sent to the IEEE Standards Review Committee for approval.

Dr. Jeff Dahn of Dalhousie University opened the discussions on lithium-ion technologies, reporting on his efforts to develop a “drug store” lithium-ion cell, or one that can be used to replace consumer nickel cadmium, nickel metal hydride, and alkaline cells on store shelves. The key issues that need to be addressed in this effort are safety, cost, energy density, performance, and charge control. Safety is the most important and needs to be “bullet- proof.” Cost needs to be similar to NiCd and performance and energy density better than NiCd and NiMH. Dahn discussed each of these points and identified potential solutions for most of them. The recommendations included the use of LiFePO4 and graphite or Li4Ti5O12 as the electrodes and LiBOB (lithium bis[oxalate] borate) as the electrolyte salt. The one area that still needs closing in on is the identification of a “shuttle” type mechanism as a means of improving charge control safety to help bring a lithium-ion cell to the consumer market.

Guoying Chen from Lawrence Berkeley Labs presented an interesting technique for improving the safety of lithium-ion cells that utilizes electro-active polymers to prevent overcharge and over-discharge during cycling. The technique involves using polymers that become conductive at certain voltages. An electro-active polymer material is combined with a commercial micro-porous separator to form a composite membrane for use as a separator in the battery. These membranes were evaluated in Li-TiS2 and Li-Li2Mn4O9 cells. When the voltage of the battery goes above the cutoff voltage of 3.2V, the polymer becomes conducting and shunts the current between the electrodes so that lithium is not overcharged. Development of polymers that could behave similarly at 4V will require further work.

Yazid Saidi of Valence Technologies reported on their efforts to identify alternative cathodes for the lithium-ion system. They have focused on the lithium metal phosphates as the most promising next generation materials for cathodes. These are generally olivine phosphates, and their structure prevents the lithium-ion from moving in a non-linear fashion by confining its movement to one-dimensional tunnels. One example given was Li3V2(PO4)3, or lithium vanadium phosphate. Test results demonstrating greater than 450 cycles were presented for this cathode material as well as results for lithium cobalt phosphate and lithium iron phosphate,

Denis Geoffroy of Phostech Lithium reported on their efforts to develop materials based on LiFePO4 using carbon-coated phosphate particles to improve the performance and safety of the system. The carbon-coated materials offer higher power capability than pure LiFePO4. They reported the ability to achieve 60% capacity at 10C rates and up to 60mAh/g at a 40C rate. They are continuing their efforts to optimize the carbon content of the material to maximize performance and have identified high and low power grades for specific applications.

Dr. Brian Barnett of TIAX discussed the general effort to develop alternative cathode chemistries for use in lithium-ion batteries. The goal of these efforts is to improve the stability and safety of lithium-ion cells. There is an increased desire to look at alternatives to LiCoO2 because of safety reasons and the fact that cobalt prices are going up. Nickel-based materials can provide an alternative; however, safety of these types of materials must be improved. Barnett discussed some of the work at TIAX looking at adding dopants to the LiNiO2 material to improve its safety. Through chemical and quantum mechanical modeling of the LiNiO2 they identified that the safety of the system is related to stability of the base structure in the cathode material during cycling. Researchers have focused on looking at ways to add dopants that can stabilize the structure of the cathode material to prevent “collapse” of the Ni-Ni structure and allow lithium ions to continue to move freely in the system. They have achieved improved safety and high rate capability with good cycle life.

Dr. Igor Barsukov of Superior Graphite opened the session on Recent Advances in Battery Technologies and Applications with a discussion of nano-sized graphitic compounds to improve conductivity in power source applications. Superior has partnered with Columbian Chemicals Co. to develop a new nano-sized material called Pureblack™ Carbons. These are partially graphitized, nano-sized carbons that give improvements over acetylene black and other carbons in power applications. The starting carbon is a high quality furnace black that is then heat treated by Superior. The heat treatment then partially graphitizes the carbon and produces a purer material. Electrochemical testing shows that the Pureblack carbon significantly improves the performance of EMD cathodes over those with synthetic or battery grade carbon black.

Dr. Brendan Coffey discussed developments in high rate cylindrical alkaline technology at RBC Technologies. RBC mainly has been associated with alkaline rechargeable systems; however, this is a primary Zn/MnO2 system that provides two to three times the energy capability of standard alkaline cells in high rate discharges. Coffey presented data showing that the RBC technology can provide high energy content at high rate and maintain that energy content at low-rate discharge. The technology uses similar materials to those in standard bobbin alkaline cells but differs in internal construction. This allows increased anode-to-cathode interfacial surface area and improves the rate capability of the cell. The most impressive performance improvement is seen in simulated digital camera pulse testing as shown in the graph on page 20, where the RBC technology outperforms both standard and premium alkaline cells by two to three times. RBC is continuing its development of this technology and plans to have pilot line capability in place by the end of 2004. Coffey also reported that RBC is developing a prismatic version of this technology and showed preliminary test results indicating discharge capability of 1.3Ah to 1.0V in a 7/5 F6 size cell at 500mA discharge rate.



Jane Blasi from Duracell introduced two new prismatic designs being offered to consumers, one a “gum pack” primary alkaline cell for audio devices (LP1), shown at left below, and the other a prismatic lithium primary battery (CP1) for digital camera applications. The LP1 cell is a thin prismatic cell and its specifications indicate it can deliver 1460mAh at a 50mA discharge rate. The devices that can use this cell are somewhat limited today but the trends in the market show an increasing demand for this form factor with market projections showing LP1 compatible devices at approximately 20% of new sales by 2008. Duracell is working with device OEMs to further enhance the growth of devices suited for this technology. The CP1 lithium cell delivers 2300mAh at 35mA and is a direct replacement for the NP-60 lithium-ion battery. Currently 33% of cameras that use prismatic cells use the NP-60 battery and this is expected to grow to 39% in 2004.

The battery offers consumers the convenience of being charged when purchased and the ability to carry spare batteries without the need for a charger. Duracell is also working with OEMs to expand the device compatibility for this technology. Blasi reported, too, that Duracell is monitoring the power/energy needs of new and emerging devices and is committed to delivering power sources that suit the needs of OEMs and consumers. Future work at Duracell includes the prismatic format cells, air-managed zinc air, fuel cells and new chemistries.

Stefan Pfrommer from Renata reported on the development of batteries for a new application in tire pressure monitoring systems. These batteries are used to power RF systems that report tire pressure in vehicles. This is a growing market, mainly due to the U.S. government requirement that all new passenger vehicles have this type of system by 2006. As one can imagine the operating environment is extremely rugged with some of the requirements being 10-year operating life, operating temperature range of –40C to 85C, operating voltage between 1.8 and 2.4V, shock, vibration, and acceleration tolerance. The most likely candidates for this application are LiMnO2 and LiCFx batteries. Pfrommer reported on the progress Renata has made in developing the LiMnO2 system and that Renata is already supplying this type battery for TPMS applications.

This year the conference included a session on Small Fuel Cells. This began with an overview of micro-electro mechanical systems (MEMS) technologies presented by Valluri Rao of Intel. He presented details on MEMS technology itself, discussed its relevance to micro fuel cells, and provided some examples of possible applications for fuel cells. MEMS are 3-D structures with micron-size lateral dimensions fabricated using IC compatible batch processing techniques.These devices can include mechanical sensing and movement/actuation mechanisms. Today there are still many issues to overcome in producing MEMS devices that are reliable and long lasting, although a significant amount of research is ongoing to overcome these problems. For the micro fuel cell, MEMS technology can help develop miniature pumps and valves that can assist in the operation of the fuel cell. The technology can also be applied to providing micro fluidic channels for fuel flow and micro reactors for reformer processes.

Stephen Voller of Voller Energy, a U.K. company, reported on developments of portable fuel cell systems they have developed for use in recharging batteries in portable devices. These systems take advantage of the combination of a constant output from the fuel cell combined with a rechargeable battery to supply long-running power for portable devices. The battery can supply the instant-on capability for the device while the fuel cell supplies the power for long-run applications. Voller showed photographs of models of the fuel cell charging system they have developed for this purpose.

Dr. Shailesh Shah reported on advancements in hydrogen storage and development of fuel cell technology for portable products at Millenium Cell Inc., a company that licenses enabling technology developments for the hydrogen economy. Their prototype systems utilize sodium borohydride as a system for storing and generating hydrogen for the fuel cell. Shah showed prototype designs for PDA and consumer electronic devices. He also discussed the Hydrogen on Demand™ hydrogen generation technology developed by Millenium Cell.

Jim Kaschmitter of Ultracell reported the development of a new reformed methanol micro fuel cell stack that produces 20W in about 60cm3 of volume. Both the reformer and fuel cell are fabricated on silicon chips. He said the UltraCell FuelChip-based fuel cell yields substantially better performance than DMFCs. Kaschmitter described three applications that they have developed, one for a laptop computer and the other two for separate military products. In the laptop application there is an opportunity to replace a nine-cell lithium-ion battery pack and achieve a 2X performance improvement. For the military application the opportunity lies in the possibility of a 70% reduction in weight.

Dr. Jürgen Pawlik of Celanese Ventures GmbH, reported on developments of membrane electrode assemblies for PEM fuel cells. These MEAs are PBI-based and are marketed under the Celtec® brand name. The membranes are an alternative for Nafion® and provide improved performance in DMFCs. Celanese is continuing development of these membranes to improve their power density.

Dr. Mark Hampden-Smith of Cabot Superior MicroPowders provided an extensive overview of fuel cells that included a discussion on issues and challenges facing this industry. These included performance, packaging, miniaturization, conversion efficiency, reliability, consumer acceptance, and safety. One area of particular focus is catalyst materials and catalyst distribution. CSMP has developed powder production techniques that allow it to customize materials for particular applications. In the fuel cell area they have produced electro-catalysts for DMFC applications that can achieve 35mW/cm2 at loading of 4mg/cm2. CSMP can custom-engineer particles for the energy, electronics, and display industries, among others.

Dr. Franz Kruger of LTC/GAIA reported on their development of high energy and high power lithium-ion polymer batteries for HEV, military and stationary applications. The HEV battery consists of 80 6Ah cylindrical cells and has specific power of 1500W/kg and power density of 3750W/l. Their military battery is based on the BB-2590 form factor and uses fast-charge D cells. The stationary battery example was a 48V/60Ah battery for traction or backup communications applications. LTC/GAIA has developed a full range of high performance cells in both prismatic and cylindrical formats.

Yasunori Ozawa of ENAX, reported on development of lithium-ion batteries for electric bikes. The 36V, 7Ah battery uses prismatic pouch 3.6V, 7Ah cells. The battery has energy density of 235Wh/l and a specific energy of 118Wh/kg. ENAX is currently selling this bike and various other battery products in Japan.

The conference closed with a presentation by John Broadhead of Battery Intelligence™ Inc., on the use of “fuzzy logic” to monitor the state of charge (SOC) and state of health (SOH) of various battery chemistries. His discussion described various methods developed and techniques used for improving the monitoring of battery systems and improving the ability to predict performance trends in the systems.