28May 2015

Mary Meeker is a venture capitalist at Kleiner Perkins who publishes annually a report on internet trends. Her 2015 report can be found here. One can find some interesting insight and subtle observations on how our new digital society is evolving and using technology. At the highest level, it says our society is going, or perhaps a more appropriate tense, has gone, mobile. It is not surprising. We see it in the office with our colleagues, at home with our teen children, with strangers on the streets, cafes and trains, and even in remote travel locations where economies rated as developing or underdeveloped are adopting mobile at a rapid rate. Just look at internet penetration in India, China, Asia and Africa. Social media, e-commerce, revolutionized services, and instantaneous communication are some of several drivers. We hear now a new saying: Mobile is Uberizing the world.

This broad mobile transformation of society is and will for the foreseeable future remain powered by the lithium-ion battery. We cannot conceive of a world let alone a mobile society without a compact, cost effective, portable and safe energy source like the lithium-ion battery. As much as the battery has enabled mobility, a mobile society is and will continue to drive and enable the evolution of the battery, regardless of how challenging it may be. The stakes are just too high now!

One of Mary’s slides shows the number of hours an average adult in the US spends in one single day glued to a screen watching or working on digital media.

In the course of seven years, since the iPhone was first introduced, we have tacked 2.5 hours of viewing time reaching a total of nearly 3 hours of screen time on mobile devices alone. This includes time checking email, tweeting and posting messages on Facebook, booking your next vacation and following your stocks…etc. This growth corresponds to doubling in the last 4 years, not quite as fast as Moore’s Law but certainly a lot faster than the annual increase in energy density in lithium-ion batteries. Will this trend continue? I don’t know, but if it does, we are looking at 8 hours or more of daily screen utilization on a mobile device by 2020, and that will most certainly put some serious strains on today’s battery technology.

Batteries with an energy density near 600 Wh/l were first introduced in the market around 2013 and continue to be state-of-the-art batteries today with a capacity near 3,000 mAh. It is widely accepted that for a standard 5-in mobile device, such a capacity is sufficient for a solid and honest full-day operation.  But if the trend is to increase the utilization per day by an additional 5 hours by 2020, then batteries ought to be sized to last longer. That is a very tough ask when energy density is barely increasing at 4% per year.

The answer: barring a surprise revolution in materials discovery, the answer is fast charging, unless consumers are willing to accept bulkier, thicker and heavier smartphones, a trend that is not showing any signs of life. But fast charging is not only the ability to put charge in a battery at a fast rate, but also the infrastructure supporting it, from the proper chipsets to AC adapters, cabling…etc. With new chipsets from manufacturers like Qualcomm supporting new high power protocols (e.g., QC 2.0), new standards in particular the new USB Type-C, and clever battery management and charging algorithms similar to the ones developed here at Qnovo, fast charging will become a standard in the coming few years, allowing the end user to charge multiple times in one day without the agony of having to wait hours for a charge.

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