May 11, 2012

Lithium-Ion-Battery – Advantages and Disadvantages– Part 2

Part of the challenge in a product liability or personal injury case is understanding the factors contributing to product failure. This understanding can assist attorneys in selecting the appropriate expert witness.

This week’s article is a follow-up to a previous article which discussed trends in lithium batteries.

Li-ion batteries are widely used in portable electronic devices such as cell phones, cameras, personal computers, power tools and electric vehicles.
Battery and application developers have found that advantages of Li-ion batteries far outweigh their disadvantages. Some of the attractive performance advantages of Li-ion batteries as compared to aqueous batteries (lead acid, nickel-cadmium, nickel-metal hydride) are:  

  • 3.6+ operating voltage.  For example, it replaces three nickel-metal hydride cells
  • No leakage. No free liquid in a cell.
  • High energy density, about 25% the weight of lead acid cells, makes it the choice for electric vehicles.
  • Solid state chemistry allows for very small thin batteries, such as printed batteries.
  • Li-ion batteries offer large 1000 AH (amp/hour), high 40C discharge rates for heavy duty starters, heavy traction vehicles , and tool applications.
  • High efficiency on charge and discharge; high rate charge; deep discharges of 80%.
  • Low self-discharge rate, allowing shelf life of 5-10 years is possible.
  • Performance and safety are extended with the use of industry practices such as battery management circuitry. The use of power management results in lower battery energy requirements.
  • Cell conditioning is not required for Li-ion batteries.
  • Many chemistry variants, in different configurations, constructions and capacities of Li-ion cells are available.
Li-ion batteries do have some disadvantages however:  
  • Prices of lithium batteries are premium. The costs are decreasing as process  development continues.
  • There are safety concerns using Li-ion cells because of the use of high energy materials.
  • There are problems with over charge and over discharge. 
  • The internal resistance is high for Li-ion batteries as compared to aqueous systems.
  • Thermal runaway and venting can occur when cells are crushed or punctured. Such conditions can cause fires.
  • Elaborate protective circuits, such as battery management circuitry, are required; these are available and  routinely used.
                                                                                                                                         
The author of this blog post has a Ph.D. in Physical Chemistry from the University of Vermont. His experience includes developing lithium battery power supplies and starting a manufacturing line for lithium battery power supplies. Click  to read more about this technical expert witness.

The Project Managers at CECON are technical experts themselves with testifying and real world industrial and scientific experience.  Their professional expertise allows them to assist in identifying the expertise their clients may need for a case.


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