What Drives Battery Evolution?

Hi Innovators,

I was reading about battery as one of the key barriers for mobile technology evolution. The capacity of battery has increased only 2 times in last 10 years whereas processing speed has gone 12 folds up. Here is a graph I came across showing Battery evolution with time.

          I am just wondering, what is actually changing over time. Does it follow the TRIZ laws of technology evolution? At least two major trends I know

  1. Increasing Contrability and Dynamics

  2. Moving from MACRO to micro (Field changes from Mechanical –>Thermal –>Pneumatic /Hydraulic–>Chemical –> Electrical–> Electromagnetic) 

Apparently I am not able to link the battery trend with evolution priciples. Your views will help to bring more insights.

Source : http://www.greenelectric.com.my/index.php?option=com_content&view=article&id=66&Itemid=93