As demand accelerates for smaller, higher-performance mobile electronic devices, the search for proper battery power and design is becoming a key part of the technological race.
Lithium-ion polymer battery (LiPB) technology is a perfect match for cell phones, laptop computers, PDAs, and future devices that require a battery technology that provides a balance between size, weight, and energy.
Demand for mobile telephones shows no signs of slowing down. According to the Cellular Telecommunications Industry Association, there were more than 86.1 million wireless subscribers in the United States as of Dec. 31, 1999. This is equivalent to more than 31% of the U.S. population.
Experts estimate that by 2005 there will be more than 1.26 billion wireless-phone users around the world.
The corresponding demand for batteries is staggering, but it creates a great opportunity for battery manufacturers developing new technologies, as well as OEMs designing portable devices that need to be smaller, lighter, and faster.
Until now, commonly used batteries included the nickel-cadmium (NiCd) and nickel-metal hydride (NiMH) chemistries typical in cell phones, and even the newer lithium-ion (Li-ion) batteries, which are used to power higher-end devices. When LiPBs become available in high volume, the chemistry is expected to challenge and replace NiMH and Li-ion batteries as the preferred power source for portable electronic devices.
LiPB technology delivers the best energy density available for rechargeable batteries. LiPB and Li-ion batteries have similar characteristics. Both offer power in the 3- to 4.2-V range, compared with 1.2 to 1.5 V for NiCd and NiMH cells.
LiPB technology emulates the life-cycle benefits of the Li-ion chemistry, providing 500+ charge/discharge cycles with no memory effect. Furthermore, the voltage, energy density, and cost make LiPB the leading contender for future electric vehicles.
LIPB technology is less than 4 mm thick, but does not sacrifice energy density and power, whereas the thinnest liquid Li-ion cells are about 5 mm thick.
LIPB technology has virtually limitless design flexibility. The solid polymer cell can be configured to any size, and the cells can be stacked to produce ultrathin battery packs with a broad array of voltages and capacities. This allows the battery to complement the design and available space of the electronic device rather than create a gaping cavity in the blueprint to accommodate a cumbersome power source.
Flexible cell geometry provides enormous potential for innovative designs and space savings. For example, the elements of a LiPB can be positioned flat behind a laptop screen or under the keyboard or built into the casing of a cell phone.
Manufacturing and materials are cost-effective. Lithium, refined from naturally occurring salts, is abundant and affordable.
Lithium-ion-polymer technology permits volume production through a simple, straightforward high-speed, high-quality automated manufacturing process.
LIPBs are environmentally friendlier than other batteries, especially nickel-based chemistries. The materials used in the solid-polymer Li-ion system, including the metal oxide in the cathode, are benign.
OEMs can count on LiPB technology to provide both energy and structural functionality to electronic devices, taking them a step closer to optimal efficiency. The cost-effective nature of LiPBs allows OEMs to use them in a variety of applications, not just high-end products.
LIPBs are the most technically advanced rechargeable power source available, and the technology is just at the onset of its commercial usefulness.
Sunwook Kim is chief executive of Ness Co. Ltd. in Soowon, Korea.