Multi-stepCharging
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Apple patent application points to denser batteries, improved charging technique
Some might think a ten-hour Macbook battery mighty fine, but we're happy to say that Cupertino's not quite satisfied. AppleInsider spotted a pair of Apple patent applications detailing a improved way of juicing up those lithium-polymer cells, which should greatly increase the number of recharge cycles they can endure -- or, optionally, allow Apple to use denser batteries that last longer on a charge. We'll break it down for you: the graph in the upper-left shows how Li-ion batteries currently charge, first very rapidly (constant current, increasing voltage) and then more slowly (constant voltage, decreasing current) to top the cells off. What Apple's proposing is the multi-step method depicted on the right, where current and voltage trade off, to charge the battery while being far less harsh on the physical chemistry of the electrodes inside. As you can see in the bottom graph, the multi-step CC-CV cells lose much less of their potential after 300 recharge cycles, but that's not all Apple's cooking up -- the company figures that it can increase the thickness of the electrodes to improve battery life (by as much as 28Wh/L, according to one chart) without negative effect thanks to the softer charge. Sure, we'd rather have plant-eating graphene supercapcitors, but this sounds like a plan for now.
