White Papers
Using Lithium Polymer Batteries In Portable Devices
Lithium polymer batteries have become common in single-cell consumer applications like cell phones and MP3 players, but industrial and commercial applications are now putting them to good use as well. The thin and custom shaped cells are now used in large, complex packs. This white paper is an overview of the advantages, disadvantages and guidelines for using Lithium polymer based battery packs. It looks at Lithium polymer cells versus metal-cased cylindrical and prismatic Li-ion cells and gives a brief description of battery pack construction considerations.
Upgrading to Li-ion from Lead Acid
Both the Lithium-ion (Li-ion) and Sealed Lead Acid SLA) battery markets are expected to grow over the next several years. Applications with high voltage and capacity requirements are adopting Li-ion technology because of its many advantages- especially the high energy density, small size and low weight that this technology provides. Historically, SLA batteries have had a few superior technical traits, in addition to their extremely low cost, that have kept them leading the majority of the overall battery market. However, recent innovations in Li-ion chemistry has made it extremely competitive in markets that are weight sensitive and inconvenienced by SLA’s need for frequent maintenance. Many devices have required batteries for power back-up and these are primed for direct Li-ion replacement of SLA. In the medical market alone, these applications include infusion pumps, ventilators, wheelchairs and workstation carts. This paper will outline the technical and business considerations involved in converting an existing product from SLA to Li-ion.
Making Lithium-ion Batteries Meet MIL-STD-810
The military standard MIL-STD-810, “Department of Defense Test Method Standard for Environmental Engineering Considerations and Laboratory Tests” specifies the equipment’s environmental design and test limits that it will experience throughout its service life, and establishes test methods used to measure the effects of the environment on the equipment. MIL-STD-810 Testing addresses a broad range of environmental conditions that include; low pressure for altitude testing, exposure to high and low temperatures, temperature shock (both operating and storage), rain (including wind blown and freezing rain), humidity, fungus, salt fog for rust testing, sand and dust exposure; leakage, acceleration, shock and vibration. MIL-STD-810 is typically specified for military products, but commercial products will commonly reference aspects of MIL-STD-810 as well. Custom batteries can be built to meet all the requirements, but the more challenging requirements for batteries include immersion, shock and vibration, high temperature performance, and low temperature performance. This white paper will focus on overcoming these design challenges for handheld and portable batteries.
Li-ion Battery Temperature Trends During Charge and Discharge
Lithium chemistry batteries are replacing Sealed Lead Acid (SLA) and Nickel Metal-hydride (NiMH) types in many fixed and portable applications due to their higher energy storage density relative to both weight and volume. As larger Lithium chemistry batteries are designed, managing the waste heat generated by the ever higher high charge and discharge currents becomes an increasing challenge.
Designing and Optimizing Battery Systems for Mission-Critical Portable Applications
This primer provides both electrical and mechanical guidelines for a battery pack as an integrated system. Topics include battery chemistry options (alkaline, lead acid, NiMH, lithium), cell configurations, battery pack characteristics, "smart" battery management, fuel gauges, battery pack authentication, charging options, safety considerations and enclosure options. This paper also provides insight into power management considerations for the portable device.