When looking for factual information about batteries, the journey of the Internet user is full of traps. Fortunately, I found a detailled, very readable and facts-based web site. It named BatteryUniversity.com. I like a lot the 3-part articles with a lot of details (and with German translations). You will know everything about all battery technologies, learn what the memory effect is and is not, about applications (including details about hybrid cars and plug-in hybrid cars).
Just check Part 2 of the associated book, to get information about how to prolong battery life. Worth bookmarking.