How to Construct a Lithium-Ion/Polymer Battery with Imbedded Protection Circuit Module (PCM)
Michael Kovalcik
Team 10
ECE_480_FS08
Executive Summary:
When compared to other types of rechargeable batteries, the high energy density associated with lithium-ion and lithium-polymer cells makes them the ideal power source for portable electronic devices. Because of this, rechargeable lithium batteries can be found in a wide variety of consumer electronic devices such as cellular telephones, laptop computers, digital camerasand cordless power tools. In order to maximize their lifecycle and reduce safety concerns, both lithium-ion (Li-Ion) and lithium-polymer (Li-Po) cells require the use of a Protection Circuit Model (PCM) when assembled together to form a battery. The PCM may be imbedded in the charger or permanently attached to each individual battery pack. These notes will discuss the advantages and disadvantages to each method of implementation and will include step-by-step instructions for the construction of the latter, permanently attached PCM, configuration.
Keywords:
Battery, Cell, Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Po), Protection Circuit Module (PCM), Energy Density, Nickel-Metal-Hydride (Ni-MH), Nickel-Cadmium (NiCad), Lead-Acid
Introduction:
As Electrical Engineers, it is likely at some point in our careers we will have some level of professional involvement with battery operated systems. RechargeableNickel-Metal-Hydride (Ni-MH) and Nickel-Cadmium (NiCad) cells and Lead-Acid batteries are no longerthe standard rechargeable battery technologies. These threetechnologies suffer fromlower energy densities (50-112, 33-75,18-55 J/kg respectively)than conventional, one time use Zink-Carbon or Alkaline cells. This has made these onetime use batteries and cells more desirable for many consumer applications. The new generation of Lithium based, rechargeable cells have made it possible to combine higherenergy density (95-335 J/kg), relatively high nominal voltage (between 3 & 4 volts), and the ability to hold a charge for years,into a rechargeable battery that is better than onetime use batteries. Lithium technology is quickly becoming the preferred and more economical power source for portable electronic devices. The ability of lithium ion (Li-Ion) and lithium polymer (Li-Po) cellsto be charged and discharged more than 1000 times makes them much more environmentally friendly than one time use cells. Their high
“Lithium batteries have now taken their place as the rechargeable battery of choice for portable consumer electronics equipment. Though they were expensive when introduced, volume production has brought the prices down.”
Objective:
Characteristic Li-Ion
Results: