It's not news that batteries based on various types of Li-ion chemistry are taking a larger share of the market for rechargeable power sources.
They are capturing share from older, established energy sources such as sealed lead acid (SLA), nickel-metal hydride (NiMH), and nickel-cadmium (NiCd) battery packs, and in a market that itself is growing rapidly. From laptop PCs, to medical equipment, to transportation such as e-bikes, HEVs, EVs, and even aircraft (think Boeing Dreamliner), Li-ion is the way to go -- if you can afford the cost differential, of course.
According to a recent report from Lux Research, the market for energy storage in mobile applications will go from $28 billion in 2013 to $41 billion in 2018, as shown in the graph below. They also predict that Li-ion will dominate in many of the mobile application segments, reaching $37 billion by 2018. Even if you assume these forecasts are overly optimistic or have a large error band (or both), there's no denying that Li-ion brings strong technical and product advantages.
The reason for the rapid adoption of Li-ion rechargeable storage is simple: By weight and by volume, it has from three to 10 times the energy density of other battery chemistries, which makes it a very attractive proposition for many situations.
That's all well and good for the battery makers, but what about the IC vendors? The benefits of Li-ion chemistry come with technical and end-user challenges, both of which can be answered with advanced IC designs.
On the technical side: Li-ion batteries need special care when being charged, discharged, and even not in use, in both normal operational modes and in case of internal cell defects or other problems. (A few years back, there were well-documented cases of charged but unplugged and "off" laptop PCs catching fire, due to internal cell shorts; there's also the Boeing 787 Dreamliner battery-fire situation.)
As a result, these batteries need careful monitoring of their charging and discharge dynamics, temperature, and other parameters. Complicating the situation is another virtue of Li-ion technology: It has a relatively flat discharge profile, where the output voltage stays close to nominal as the cells discharge (in contrast, other chemistries have a sharper downward slope of output versus remaining capacity). This makes it hard to assess the actual state of charge of the cell, and often requires additional compensation for temperature and other variables.