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Posted on March 5, 2013 by  & 

What energy storage will power the iWatch and future smart watches?

The emerging trend in multifunctional portable devices, such as the smartphone, has caused the decline of those that previously performed single functions. This has been the case with simple digital cameras and now wrist watches.
So the recent Apple rumours of the possible launch of an iWatch is a natural step forward, as stated last year in IDTechEx's report Batteries & Supercapacitors in Consumer Electronics 2013-2023: Forecasts, Opportunities, Innovation. There is a trend among young people to use their smartphones to tell the time, when this used to be the single function of the humble wrist watch. Indeed, market figures don't lie - in 2005 the growth of the global traditional wrist watch market was around 6%, now the industry is abruptly declining at 20% yearly. It is only the luxury watch industry that is growing at a steady rate of about 5% yearly, and this should be sustained in the following ten years as emerging economies create new rich segments of the population, these people will be eager to have their first fine Swiss time piece on their wrists, the drive behind this is not the need to have digital multifunctionality but to have a status symbol.
However for the rest of the population, with the increasing influence of social networks and mobile multifunctionality, a Smart Watch will be a better fit, especially for youngsters. The Smart Watch is just one of the multifunctionality trends in consumer electronics, as can be seen in Table 1 below.
Table 1. Multifunctionality Trends in Consumer Electronics
The consumer electronics industry has changed dramatically in the past few years. Portable devices are increasingly becoming multifunctional, and not only phones which currently have many purposes (e.g. making calls, sending SMS, internet navigation, email, video playback) but cameras and other devices as well.
For example, we will see smart watches that play music and can help you manage your smartphone, or android powered cameras with applications and Wi-Fi internet connectivity. At the same time, smartphones are taking over more functions. For example, we could think of a smartphone that becomes a semi-professional camera when adding interchangeable lenses, just as the rumour of the iWatch began with an Apple patent showing this device, there is an Apple patent of this sort of iPhone that suggests the use of interchangeable lenses, see figure 1 below.
Figure 1. A patent by Apple
This trend in power demand terms is translated into frequent peak power demands from lithium and other types of batteries. The same applies to wireless sensors, which require power pulses for performing their functions. In figure 2 below we show the power demand profile for different operation modes of three different smartphones.
Figure 2. Different power profiles for different smartphone uses

Supercapacitors fit well into the emerging energy storage landscape

As in any other battery, energy and power will play against each other; increasing one will lead to the loss of the other. Accordingly, the capacity of lithium batteries (energy content) is reduced if we extract the energy quickly. This means that if we require high power from the battery we will extract less total energy than if we require low power (see figure 3).
Figure 3. Specific power vs specific energy
Source: Venkat Srinivasan
As seen in Figure 1 the multifunctionality trend in smart portable devices requires different power profiles depending on the function, some of these high power demands are required more often. These variable power demands mean less available total energy extracted from the battery (and accordingly, the battery running out quicker). In the consumer electronic industry this was not a problem in the past, since the mobile phone power demand profile was more or less constant and low. This was the case because mobile phones were only used to perform one function (i.e. make calls).
In consequence, lithium battery technology capabilities are being challenged by the modern multifunctional portable devices, which increasingly require higher performance in terms of power density. Whilst current research and development pathways aim for the emergence of a new generation of high energy density technologies, alternative energy storage technologies are challenging the dominance of lithium batteries.
This is the case with supercapacitors, which are an emerging energy storage technology whose characteristics make them strong candidates for satisfying those specific functions where lithium batteries underperform.
Interestingly, supercapacitors can deliver a considerable amount of energy at high power (see Figure 3). These characteristics make them suitable for supplying high power in multifunctional devices where current batteries can't provide it without reducing their total energy capacity (see Table 1 above).

On the other hand, batteries and supercapacitors are becoming thinner, flexible and now paintable!

Having thinner consumer electronics is another no-brainer, however how thin can they get? Currently the thinnest is the Finder with a thickness of just 6.6 mm. It uses a battery of just 4 mm (See Figure 4 below). Printing batteries is the next technology evolution for the manufacturing of the required energy storage solution for future consumer electronics. But it does not just make them thinner, they can be flexible too.
Figure 4. Mobile phone trend
Source: IDTechEx
Figure 5. A flexible phone, the Nokia Kinetic
Source: Nokia
Companies such as Front Edge Technologies have developed solutions such as the NanoEnergy® which are thinner than a piece of paper and when embedded in micro devices such as smart cards and portable sensors, act as an autonomous power source enabling new functions which greatly add to their value. They are flexible as well, see figure below.
Figure 6. Flexible energy storage
Source Front Edge Technology
Finally batteries can be paintable, such as the ones currently in development by Rice University!
Figure 7. Paintable batteries
So the idea of the iWatch is just the tip of the iceberg. To learn more follow our research.
IDTechEx's report, Batteries & Supercapacitors in Consumer Electronics 2013-2023: Forecasts, Opportunities, Innovation leads you through the basic concepts to understand the technologies in the energy storage industry for Consumer Portable Devices, including the advantages and limitations of different technologies.
Top image: BGR

Authored By:

Principal Analyst

Posted on: March 5, 2013

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