Reality Check: “Putting Things In Perspective"

Batteries are a ubiquitous part of our lives today. Since batteries range from smaller than credit cards to the size of power plants, there is no universal solution. The more we understand about the factors that drive cell performance and the relation between cell design and application requirements the faster will we advance the technology and the better that we will design products? We have all seen the press releases for laboratory research that claim incredible breakthroughs in the capacity of their lithium-ion batteries. And marketplace advertising leads engineers to specify requirements that aren't needed, which ultimately translates into reduced performance in the applications. For example, silicon has ten times the capacity of carbon anodes, but what does that translate to in a real finished battery? Or the ad says 75C discharge rate, but do you need that for your cell phone, and what does that cost in capacity? This presentation will look at the realities, and provide an insight into the contributions of various components of the cell to the specific energy and energy density of the cell, as well as the cost of specifying performance that is not needed. In addition, several specific examples of unique requirements that invite unorthodox solutions will be presented as food for thought. These basic analyses can help researchers, application engineers, managers, and corporate planners to value and direct resources.