Some of the initial coverage on the new 3rd generation iPad suggested that Apple somehow increased the power density of the Lithium-ion battery cells inside the new iPad in order to achieve the jump from 25Whr, in the iPad 2, to 43Whr — that’s more than a 70% increase in battery capacity. The reasoning behind this was that while there was this huge increase in battery capacity the new iPad is only very slightly thicker (just 0.6mm) and heavier than the iPad 2.
Now, the iPad 2 was practically all battery already, so somehow it made sense that Apple had magically created a new battery technology without anyone catching wind on it.
That would be some awesome news for the entire consumer electronics industry and you know how much we deplore mobile devices that don’t offer full-day battery life and how we are always on the lookout on ways to keep us powered on the go. However, if you knew anything about the evolution of battery technology you’d know how slowly and incrementally power density has improved.
Though we are pretty sorry that we won’t be able to now power all our gadgets for days, Apple did something different; it managed to squeeze even bigger batteries inside the new 3rd generation iPad.
As the new iPad teardown has revealed, there are three 14.6Whr batteries, measuring 125 x 65 x 4 mm each, by comparison the iPad 2’s batteries measure 108 x 63 x 2.7mm. That’s a total volume of approximately 98cm3 taken by the three battery cells in the new iPad against 55cm3 in the iPad 2, or an 77% increase.
The power density is pretty much the same for the two iPad batteries, and from a very rough calculation it comes to around 0.45Whr/cm3.
Apple obviously wanted to keep quoted battery life a constant 10 hours between iPad generations, and the increased demands from the new quad-core graphics unit, the new retina display and extra RAM meant a bigger battery was needed.
Unfortunately there is one caveat to this, the new iPad 3 will take longer to charge, with early reviewers claiming it take several hours longer to charge fully compared to the iPad 2. Well we can’t have everything, can we?
[images courtesy of iFixit]
